Uniforms worn by the Regular Army of the United States during the Mexican War were based on regulations adopted in 1832 when the uniform was completely redesigned. Facing colors worn on the uniform of America's armies from the Revolutionary War were restored, those being: buff for generals and staff; white for infantry; and red for artillery. Three uniform sets were authorized: a dress uniform; a winter fatigue uniform; and a summer fatigue uniform. The winter uniform was worn by all ranks during the Mexican War, although some officers and units wore the dress uniform.

Officer's rank was denoted on shoulder straps of the fatigue uniform, and on epaulets of the dress uniform. All officer shoulder straps were bordered in gold except for the infantry who wore shoulder straps with silver borders.

Colonel

Major

The insignia denoting rank is shown below.

Above is the shoulder strap worn by Major William H. Polk, an original member of the Aztec Club, and brother of then President James K. Polk.

Non-commissioned officers wore chevrons patterned as above on their fatigue jackets. From left to right, top row: Corporal, 2 chevrons; Sergeant, 3 chevrons; First Sergeant, 2 chevrons with a diamond below. Second row: Quartermaster Sergeant, left, and Sergeant Major, right.