The uniforms of the United States Army distinguish soldiers from other service members. The two primary uniforms are the US Army Combat Uniform, used in operational environments, and the US Army Service Uniform, worn during formal and ceremonial occasional.

US Army Combat uniform

The Army Combat Uniform (ACU) is the utility uniform worn in garrison and in combat zones by the U.S. Army. The uniform features a digital camouflage pattern, known as the Universal Camouflage Pattern, which is designed for use in woodland, desert, and urban environments.^[1] The ACU jacket uses hook-and-loop-backed attachments to secure items such as name tapes, rank insignia, and shoulder patches and tabs, as well as recognition devices such as the American flag patch and the infrared (IR) tab. Three U.S. flag insignia are authorized for wear with the ACU: full-color, full-color IR, and subdued IR. The U.S. flag insignia is worn on the right shoulder pocket flap of the ACU coat. Unit patches are worn on the left shoulder, while combat patches are worn on the right. Only pin-on skill badges and shoulder tabs are authorized for wear. In the field, the jacket may be replaced by the flame resistant Army Combat Shirt when worn directly under a tactical vest. Soldiers operating in Afghanistan will soon be issued a "Multicam" pattern better suited to that country's terrain.

US Army Service uniform

The standard garrison service uniform is known as the "Army Service Uniform." It will replace the "Army Greens," or "Class A" uniform, which had been worn by all officers and enlisted personnel since its introduction in 1956, when it replaced earlier Olive Drab (OD) and khaki (and Tropical Worsted or TW) uniforms worn between the 1890s and 1985. The "Army Blue" uniform, dating back to the "Virginia Blues" of George Washington's first command, in the Colonial Virginia Militia, which previously served as the Army's formal dress uniform, was phased in to replace the Army Green and the Army White uniforms in October 2009 and has been redesignated the Army Service Uniform. This uniform will function as both a garrison uniform (when worn with a white shirt and necktie) and a dress uniform (when worn with a white shirt and a bow tie for "after six" or "black tie" events). The blue uniform will be a mandatory wear item by fourth quarter, FY2014. The beret, adopted Army-wide in 2001, will continue to be worn with the new ACU for garrison duty and with the Army Service Uniform for non-ceremonial functions.

US Army Green Service Uniform

The main current service uniform is known as the green service uniform or "Class A's." The Army reviewed various ideas in the late 1940s in order to create a distinctive uniform. Pride in the uniform became a major issue in morale and retention, due to use of drab colors. Also, many civilian workers were mistaken for Army personnel, due to massive use of Army surplus clothing after World War II.

Army commissions reviewed various factors of design, durability and appearance. Blue was considered because of its acceptance in men's clothing, but it would then have been too difficult to distinguish it from Air Force and Navy service uniforms and the Marine Corps and Navy dress uniforms. Several colors were reviewed, and finally green (shade 44) was designated the basic color for new dress uniforms.

The green uniform has been worn with minor variations since its official adoption in 1954. The green color was adopted in order to provide a color which was more military, and distinct from various uniforms of civilian service workers. It is scheduled to be discontinued in 2014. It features a jacket with four buttons. Enlisted soldiers wear insignia denoting their branch of service on their collars. Officers wear two sets of insignia consisting of the letters "US" on their collars and their branch on their lapels.

Proficiency badges, such as the marksman's badge, are worn on the upper left pocket flap. Above this are the ribbons for medals and commendations which have been earned for various actions, duties and training. Above the ribbons are qualification badges, such as the paratrooper badges and Combat Action Badge. A nametag is worn on the upper right pocket flap. Unit awards and foreign awards are worn above the pocket, with a regimental insignia above both. Special duty badges, such as the recruiter's badge, are worn on the upper two pockets of the jacket; the side on which they are worn varies by badge, and is specified by regulation.

On each shoulder of the uniform are unit patches. The left side will have the patch of the current unit the soldier is stationed with. On the right shoulder of the dress uniform the soldier may wear the patch of the unit to which the soldier was assigned while deployed to a combat zone. Tabs indicating Ranger or Special Forces qualification, if applicable, are worn above the unit patch on the left shoulder. A similar "airborne" tab is worn immediately above the unit patch if the command is designated as majority airborne, irrespective of whether the individual soldier is qualified as a paratrooper. As the shoulder sleeve insignia generally indicates merely the general-officer command to which the soldier is assigned, the soldier's immediate battalion or intermediate-level command is indicated by distinctive unit insignia of metal and enamel, on the soldier's epaulets.

The Army Green Service Uniform has being withdrawn from issue in the fall of 2009. Only the new Blue ASU is being issued. The Army Green Service Uniform will be withdrawn after July 2014.

US Army Mess uniform

Mess dress is the military term for the formal evening dress worn in the mess or at other formal occasions. This is generally worn as the military equivalent of white tie or black tie. The Army blue mess uniform comprises the Army blue jacket, dark- or light-blue high-waisted trousers, white semiformal dress shirt with a turndown collar, black bow tie, and black cummerbund. The Army blue evening mess uniform comprises the Army blue jacket, dark- or light-blue high-waisted trousers, white formal dress shirt with a wing collar, white vest, and white bow tie. The blue trousers are cut along the lines of civilian dress trousers, with a high waist and without pleats, cuffs, or hip pockets. The trouser leg ornamentation consists of an ornamental braid worn on the outside seam of the trouser leg, from the bottom of the waistband to the bottom of the trouser leg. General officers wear pants of the same color as the jacket, with two 1⁄2–inch, two-vellum gold, synthetic metallic gold, or gold-colored nylon or rayon braids, spaced 1⁄2 inch apart. Current stated uniform regulation for mess dress is that all other officers and enlisted personnel have one 1 1⁄2 inch, two-vellum gold, synthetic metallic gold, or gold-colored nylon or rayon braid. However, regulations for the Army Service Uniform dictate that the trousers of junior enlisted personnel, specialist and below, be without ornamentation. There has been no official Army guidance as to whether this should also apply to the mess and evening mess uniforms.

The Army white mess uniform comprises the Army white jacket, black high-waisted trousers, white semiformal dress shirt with a turndown collar, black bow tie, and black cummerbund. The Army white evening mess uniform comprises the Army white jacket, black high-waisted trousers, white formal dress shirt with a wing collar, white vest, and white bow tie. The trousers are the same for all ranks.

US Army Physical training uniform

The U.S. Army currently uses the Army Improved Physical Fitness Uniform (IPFU), manufactured by UNICOR. It is essentially a tracksuit, marked with the ARMY name. It is required during Army physical training.

US Army Special Branch Uniforms

The United States Army also issues special uniforms to Soldiers in aviation fields if they serve as pilots or flight crew members and other special uniforms are issued to medical and food service personnel.

Aviation uniforms historically include the one-piece flight suit, constructed of flame resistant Nomex fabric, which have been issued in Olive Drab Green or Desert Tan, depending upon the area of intended use. The current flight-approved uniform is the Army Aircrew Combat Uniform (A2CU), which is outwardly similar to the ACU. Outside differences to the ACU include: Sleeve pencil pocket flaps, velcro closures on all pockets, flight-suit style thigh pockets, and the addition of lower leg pockets, oriented in similar fashion to the flight suits. The A2CU is also constructed of Nomex, similar to the flight suit so as to present a smaller risk of fire-related deaths in aviation accidents.

Medical personnel may wear unit-issued hospital scrubs, but the official uniform for medical personnel assigned to medical activities such as hospitals and clinics include white pants, different versions of white shirts for male or female Soldiers, black or white low quarter shoes, and accompanying insignia. A personally purchased white cardigan can be worn with this uniform in addition to other authorized uniform items. Food service personnel may receive exactly the same uniform as male and female medical personnel with differing accoutrements, and mess hall supervisors may a similar uniform with black pants.