Imperial Guard Regiment
A regiment is the primary organisational unit of the Imperial Guard, and of the Imperial Army ground forces before that. The size and composition of Imperial Guard regiments is not standardised across the Imperium; the number of individual Guardsmen alone can vary enormously between regiments, with some only a few hundred strong at founding-strength, whilst others possess tens of thousands of fighting troops.
The root of this non-standardisation is the fact that every world that produces Imperial Guard regiments has its own martial traditions, practices and experiences which all combine to dictate the manner in which its inhabitants choose to wage war. Despite this, it is possible to classify Imperial Guard regiments into different types by the nature of their equipment, training or battlefield role. An important point of similarity between regiments is also present in their organisation; each different regiment type is divided in a fairly similar manner within that classification.
A regiment is divided into a number of fighting units notionally called companies, each with a command staff of its own. Each company can consist of a number of further sub-units again notionally called platoons, each platoon in turn being made of a number of individual squads of Guardsmen. The actual terms used for these fighting units, their numbers and equipment typically varies somewhat between regiments.
Types of Imperial Guard Regiment
Light Infantry Regiment
A regiment formed up with no organic fighting or transport vehicles is known as a Light Infantry Regiment. These regiments display tendencies towards battlefield infiltration and reconnaissance, display skill at moving through all manner of difficult terrain and often possess highly effective sniper cadres. They tend to be somewhat deficient in heavy weapons options.
Some regiments exist within the Imperial Guard who specialise in arriving on the battlefield from the skies. Such regiments are termed Drop or Drop Troop Regiments. Lightly armed and equipped (although not as light as Light Infantry), Drop Troop Regiments typically attack from behind enemy lines, or are dropped right on top of enemy defences. All personnel in a Drop Regiment will be able to be equipped with grav-chutes, although this is not their only method of attack. Such regiments will also feature a large amount of airborne vehicles such as the Valkyrie troop carrier or Vulture gunship.
With no tanks or other heavily armoured vehicles to land in an assault, the highly mobile drop regiments are often tasked with forming the initial beachhead in an assault or capturing and holding an important location until the armoured reinforcements can arrive to relieve them. This means that the casualty rate amongst Drop Regiments tends to be higher than that of "regular" Imperial Guard units, as the regiments are ill equipped for a protracted fight with a superior force.
Regiments of Drop Troops often make use of specially adapted equipment such as Drop Sentinels, Cyclops Demolition Vehicles and Sentry Guns. These machines are often dropped into combat via Grav-chutes alongside the Troopers or deployed from the holds of Valkyries.
A 'standard' Imperial Guard regiment will feature a predominance of fighting Guardsmen, as well as a number of organic fighting and transport vehicles. Despite being percieved as the most common of regiment types, the variation between Infantry regiments of different worlds will be marked.
Heavy Infantry Regiment
Similar in style to Infantry Regiments, Heavy Infantry Regiments are marked out by the personal equipment of their Guardsmen. Almost all troopers in a Heavy Infantry Regiment will be equipped with heavy armour, such as carapace armour or a more exotic design unique to their world of origin. Similarly, weapons issued will be of a 'heavier' nature with a preponderance of plasma or similar high-end energy weaponry issued to specialists and teams. It has been known for all troopers in a Heavy Infantry Regiment to be armed with hellguns instead of the standard Guard weapon, the lasgun.
Mechanised Infantry Regiment
A regiment where all infantry units possess their own organic transportation. Mechanised regiments feature a preponderance of the Chimera vehicle, but may also feature other transport vehicles, including designs unique to their homeworld. Mechanised formations can often be found providing support for armoured units, and may possess armour of their own, amongst other variations of fighting vehicle.
The hammer of the Imperial Guard, Armoured Regiments are made up entirely of fighting vehicles, and can be expected to field very high numbers of Leman Russ Battle Tanks or variants. Typically bereft of organic infantry, but many contain their own artillery and flak tanks. Some Armoured Regiments may also possess Super-Heavy Tank units.
Regiments made up entirely of artillery pieces are known as Artillery Regiments. Such regiments can deploy a mixture of destructive weapons types or may specialise in a particular brand of long-range ordnance. Some such regiments contain small numbers of infantry and are likely to contain large amounts of transportation and anti-air vehicles. Since Artillery Regiments are not intended for direct frontline combat, they are generally much smaller then other Imperial Guard regiments. For this reason, Artillery Regiments are often attached as auxiliary units to larger regiments or are placed under the direct control of the local Commanding Imperial Officer.
Regiments specifically trained for siege warfare often contain more artillery, both heavy and light, then standard Imperial Guard Regiments. Siege regiments often are larger and more well equipped then other types of regiments as they are expected to stay and fight in a warzone for at least several years if not decades if the war is particularly brutal. Due to the high casualties such regiments will inevitably take, siege specialised forces often have large contingents of conscripts so that the regiment's pool of manpower always remains high. Siege regiments often work in concert with Light Infantry or Armoured Regiments so that a breach in enemy lines can quickly be reinforced and if possible, pushed forward deeper. More well equipped siege regiments often have a large number of super-heavy and heavy tanks. 
Abhuman-populated worlds raise their own regiments of Imperial Guard, although very few in number. Because of the specific levels of competence and/or skills possessed by Abhumans, these regiments are normally raised only to be immediately split up into small units, which are then parcelled out and attached to other Imperial Guard regiments.
Notable Imperial Guard Regiments
|Light Infantry||Tanith First and Only|
|Drop||23rd Elysian Drop Troops|
|Infantry||Cadian 8th Shock Troops|
|Heavy Infantry||Royal Volpone|
|Mechanised Infantry||Armageddon 276th Steel Legion|
|Minervan Tank Legions|
|Artillery||Valhallan 12th Field Artillery|
|Siege||Death Korps of Krieg|
|Abhumans||Ogryns of Anark Zeta|
- 1: Warhammer 40,000 5th Edition Rulebook, pg. 138
- 2: Codex: Imperial Guard (3rd Edition, 2nd Codex), [Needs Citation]
- 3: Imperial Armour Volume Three - The Taros Campaign, [Needs Citation]
- 4: First and Only (Novel) by Dan Abnett, [Needs Citation]
- 5: The Traitor's Hand (Novel) by Sandy Mitchell, [Needs Citation]
- 6: Imperial Armour Volume Five - The Siege of Vraks - Part One, [Needs Citation]
- 7: Codex: Imperial Guard (5th Edition), pg. 12
- 8: The Imperial Infantryman's Uplifting Primer, pg. 13