The Ministry of Magic has seven departments in all, each dealing with different aspects of the wizarding world.

The Department of Magical Law Enforcement is the largest, and all others more or less answer to it, except the Department of Mysteries.

Each Department has a level of Ministry Headquarters assigned to it, although Law Enforcement has not only level two, but also the courtrooms of level ten. There are also many minor offices within the departments, which are part of an informal ranking system based on its size and perceived importance by senior officials, with transfer from a smaller division to a bigger and busier one being viewed as a "promotion."

The departments communicate through "interdepartmental memos" written on pale-violet paper aeroplanes, which fly on their own to destinations, because previous routine use of owls for messages within the Ministry caused an excess of dirtying by owl droppings and moulted feathers.

Known Ministry departments and offices include: -

Department of Magical Law Enforcement-

The Department of Magical Law Enforcement is a combination of police and justice facilities, and has power over all other departments except the Department of Mysteries.

The seal of the Department of Magical Law Enforcement is "DMLE" written in capital letters against a backdrop of outward radiating sword-shaped rays of different sizes and thin lines along all the eight directions of the compass, inside two thick concentric circles, with "DEPARTMENT OF MAGICAL LAW ENFORCEMENT" written in capital letters under the concentric circles.

The Department of Magical Law Enforcement has six offices under it, which are "Auror Office" , "Office for the Detection and Confiscation of Counterfeit Defensive Spells and Protective Objects" , "Misuse of Muggle Artefacts Office" , "Improper Use of Magic Office" and "Wizengamot" and "Wizengamot Administration Services" . The seal of the Wizengamot is a huge solid 'M' in black, with a sword-like partition in between, and two legs of the 'M' on either side balanced on a pair of black scales, and two black asterisks underneath the two measuring platforms of the brass scales, and some unknown logo in black on the top at the centre, all of it against a golden background, surrounded by a thin black concentric circle, followed by a very thick black outward concentric circle, followed by another thin black outermost concentric circle. The thick circle is engraved with "IGNORANTIA JURIS NEMINEM EXCUSAT" in gold, each word separated by four different golden logos.

Department of Magical Accidents and Catastrophes-

The Department of Magical Accidents and Catastrophes is responsible for repairing accidental magical damage.

The seal of the Department of Magical Accidents and Catastrophes is DM written in solid red capital letters and AC written in solid red capital letters separated by a solid red image of something which looks like two equally sized paper-clips intertwined together diagonally in the form of an 'X' , with a tiny solid red sun with attached outward radiating outwardly pointed triangular rays, at the center of the 'X' shape formed by the two paper-clips, all of it against a backdrop of a thinner inward circle and a thicker outward one, which are concentric, and another concentric circle of varying thickness outside the two, with "DEPARTMENT OF MAGICAL ACCIDENTS AND CATASTROPHES" written in capital letters of varying sizes, in a circular fashion, between the outermost concentric circle and the second innermost concentric circle.

The Department of Magical Accidents and Catastrophes has five offices under it, which are "Accidental Magic Reversal Squad" , "Obliviator Headquarters" , "Muggle-Worthy Excuse Committee" , "Invisibility Task Force" and "Muggle Liaison Office" .

Department for the Regulation and Control of Magical Creatures-

The Department for the Regulation and Control of Magical Creatures is responsible for studying, regulating, and controlling magical creatures. The department enforces creature law, gives licenses to appropriate applicants, handles complaints about creature abuse or misuse, and maintains two different forms of creature classification. The first form of classification is the three divisions. These three divisions are beast, being, and spirit. Every creature that is recognized by the department is placed into one of these groups.

A beast is a magical creature that does not have the intelligence to cooperate and understand magical law, nor can they help shape these laws in any way. This means they will not participate in the law-making process. This definition was given by Minister Grogan Stump in 1811.

A being is any creature that has enough intelligence to understand and cooperate with magical law, and can potentially help shape it. Typically, creatures capable of human speech are classified as a being. However, because these creatures are capable of human speech and understanding magical law, they are also capable of arguing against their given classification. Merpeople and centaurs should be classified as beings; however, they refuse to be grouped with creatures like vampires, so they are beasts. The Being Division is the most confusing of the three simply because not every creature that should be placed in this group is. When in doubt, refer to the most up-to-date listing of creature classifications published by the Ministry of Magic. The last type, spirit, are beings that have passed on, meaning they are ghosts. Because they can no longer contribute to magical law, they are then placed into the spirit category. While spirits can still speak and communicate with the wizarding world, they are not directly affected by the laws in place, so they are not permitted to contribute to the development of said laws. They are allowed to sit in on any hearings and depending on the nature of the hearing provide insight, but that is the extent of involvement they are allowed to have.

The Ministry of Magic has also created a Creature Classification Scale, to help enthusiasts realize the dangers of certain creatures. This scale is only used for creatures categorized as beasts, due to their varying nature. The classification is as follows:

X - Boring

XX - Harmless, may be domesticated

XXX - Competent wizard should cope

XXXX - Dangerous, requires specialist knowledge, skilled wizard may handle

XXXXX - Known wizard killer, impossible to train or domesticate

This classification is essential to how one goes about owning the creature and caring for the creature.

- Lesson 1, Care of Magical Creatures, Second Year at Hogwarts School of Witchcraft and Wizardry.

The seal of the Department for the Regulation and Control of Magical Creatures is a solid image of an eagle or hawk or similar bird with two solid asterisks visible on top, inside a few concentric circles of varying thicknesses, some open and some close, and "DEPARTMENT FOR THE REGULATION AND CONTROL OF MAGICAL CREATURES" written in capital letters of various sizes around the outermost circle.

The Department for the Regulation and Control of Magical Creatures has seven main offices which are "Beast Division" , "Being Division" , "Spirit Division" , "Goblin Liaison Office" , "Centaur Liaison Office" , "Pest Advisory Board" and "Office of Misinformation" . Under the Beast Division, there is "The Committee for the Disposal of Dangerous Creatures" , "The Dragon Research and Restraint Bureau" , "The Ghoul Task Force" , "The Werewolf Capture Unit" and "The Werewolf Registry and Register" . Under the Being Division, there is "The Office for House-Elf Relocation" and "Werewolf Support Services" . The Spirit Division is a single office.

Department of International Magical Co-operation-

The Department of International Magical Co-operation dealt with foreign affairs, both political and public.

The seal of the Department of International Magical Co-operation is a huge solid thick M with a circular loop in it's middle and three asterisks on one of the limbs of the loop formed by the diagonals of the M, and the letters I and C on the left and the right inside the M respectively, and "Department of International Magical Co-operation" written in capital letters of varying sizes on top of and below the M.

The Department of International Magical Co-operation has three offices "International Magical Trading Standards Body" , "International Magical Office of Law" and "International Confederation of Wizards, British Seats" .

Department of Magical Transportation-

The Department of Magical Transportation is responsible for various aspects of magical transportation. The present Head of the Department of Magical Transportation is Wilda Prodd, who has called for some interesting modernifications and modifications in the time that she has been working here.

The seal for the Department of Magical Transportation is three solid crescent moons joined to each other on their convex side and the concave sides facing outwards, one facing upwards and two facing on either side, left or right, with a capital M above the moon facing upwards, D near the moon facing left and T near the moon facing right. There is a huge white asterisk in between where the three moons meet. "Department of Magical Transportation " is written in capital letters of varying sizes below all of it.

The Department of Magical Transportation is broken down into five different offices, divisions, or sub-departments. These subgroups are the "Apparition Test Centre" , "Broom Regulatory Control" , the "Floo Network Authority" , the "Office of Magical Motors" , and the "Portkey Office" . The Apparition Test Centre takes care of various license renewals, new licenses, and other related business. The head of this particular department, Charity Dippet, is in charge of all this hubbub, and she is fortunately quite a kind and patient person. The Floo Network Authority  is the largest office. This office deals primarily with requests to set up new fireplaces with the network and with the connection, inspection, regulation, disconnection and servicing of fireplaces and sees countless request forms daily. These forms take into account the location’s type (residence, business, millennia old magical institution, etc.) as well as what kind of area it’s in, the people that use the building, the number of fireplaces in said building already connected to the Floo Network, and that sort of thing. The Portkey office is  a rather small office, and it is the job of those here to set up, approve, and monitor Portkey creation and use. There are thousands of requests for Portkey creation in any given year. These range from Portkeys for private use (which are much harder to get approved) to Portkeys used in coordinating transportation to international events. Government-requested Portkeys are not as difficult to get approved, but all who would like to legally create a Portkey must fill out several pages of forms and wait for permission before doing so, or, more likely, asking the Portkey specialists to create one for them . The Office of Magical Motors is the smallest, newest, and most confusing office. Still, it’s a very necessary one. This department was created in 2015, at the insistence of the department head, Wilda Prodd. Many agree that this addition to the Department of Magical Transportation in the Ministry of Magic was well overdue. This office deals with any forms of wizarding transportation that bridge the gap between magical and Muggle, including the fleet of company cars the Ministry boasts, the Hogwarts Express, and any other privately-owned magical methods of transportation with motors. While magical cars haven’t been terribly popular with the mainstream witch or wizard, the convenience of the automobile has proven difficult to ignore, and wizardkind is slowly latching onto the idea of making their own improvements to the machine. Other than monitoring (and, in some cases, maintaining) the motor-having transport, this office has one main function: approving the development of magical motorized transport. Any persons wanting to create a magical vehicle with a motor must be sure to file the appropriate paperwork here to obtain a permit. As you can imagine, they work quite closely with the Misuse of Muggle Artifacts Office for obvious reasons. While I’m not very familiar with this sub-department, as it was instituted after my time, I have heard that recently a permit has been given out to Flyte and Barker, a racing broom company, to begin preliminary development of a magical airplane! Can you imagine? - Lesson 2, Flying class, First Year at Hogwarts School of Witchcraft and Wizardry. The Broom Regulatory Control is in charge of brooms and their riders. All flying devices are technically regulated through this department, not just brooms. Magical creatures like Thestrals or Aethonans overlap with the Department for the Care and Regulation of Magical Creatures, and flying carpets (or other unlawfully enchanted items) also go through the Misuse of Muggle Artefacts Office, but generally speaking, this department serves as the catch-all for all enchanted flight. So, rules apply whether someone has unwisely enchanted a stick in their backyard, if someone has got a magicked toboggan, or whether someone is flying a top-of-the-line Nimbus. This office is in charge of the production of brooms by magical corporations, the sale and distribution of brooms by various vendors, and (most importantly to us today), the regulation of broom flight by the average citizen of the United Kingdom. This office also enforces height limits of flying for witches and wizards. If someone is spotted by Muggles while flying, Broom Regulatory Control will issue their family if they are currently minors or themselves, a ticket for low flying and any other necessary warnings. Multiple tickets or infractions may necessitate a broom ban and more fines. Other things can earn someone tickets as well, such as flying into a creature sanctuary without permission, loading more than the approved number of riders onto a broom, and reckless flying, but low flying is by far the most common infraction.

Department of Magical Games and Sports- 

The Department of Magical Games and Sports deals with organising sports events and enforcing game-related laws and regulations.

The seal of the Department of Magical Games and Sports is a huge M with "Department of Magical Games and Sports" written in capital letters under it. The Department of Magical Games and Sports has three offices, the "British and Irish Quidditch League Headquarters" , "Official Gobstones Club" and "Ludicrous Patents Office" .

Department of Mysteries- 

The Department of Mysteries, located on Level Nine, is a section of the Ministry of Magic that carries out confidential research regarding particular enigmas (death, time, space, thought, and love) and stores copies of prophecies. Most of its operations are carried out in total secrecy from the general wizard populace. The Department contains the following chambers in which various mysteries of life are studied, "Brain Room" , "Space Chamber" , "Death Chamber" , "Time Room" , "Hall of Prophecy" and "Love Chamber (aka The Ever-Locked Room)" .

The Ministry of Magic contains several other departments, the "Committee on Experimental Charms" , "Magical Maintenance Department" , "Ministry of Magic Public Information Services" , "Department of Magical Education" , "Very Important Members of Section M.I. Trx." , "Wizarding Examinations Authority" , "Ministry of Magic research committee" , "Ministry of Magic exploding bonbons disposal unit" and "Foreign Affairs and Sports Department" .

The seal of the Department of Magical Education is a huge solid 'M' with a sword-like partition in the middle, with "Ministry of Magic" written underneath it, with "Department of Magical Education" written below that separated by a thick black line.