Adults are 1 3/8 to 2 1/8 inch long. American cockroaches are glossy, reddish brown and have antennae that are longer than their bodies and fully developed wings. The wings of the male extend beyond the tip of the abdomen, whereas those of the female do not. Males also may fly. The smallest nymphs are grayish brown, while larger ones are reddish brown. The egg capsule is 3/8 inch long, dark brown, and usually has 8 eggs on each side.

The American cockroach is the largest pest species encountered in the northeastern United States. They are sometimes referred to as "palmetto bugs." Once formed after mating, the female will deposit the egg capsule, sometimes gluing it into place in a safe spot. A female can produce as many as 10 capsules and nymphs can hatch within 50 to 55 days under good (warm, humid) conditions. Their life cycle can take up to 2 years, therefore, American cockroaches do not have the huge reproductive capacity that other species, such as German cockroaches, do. When inspecting for American cockroaches, look low. Favored habitats include sewers and storm drains, floor drains, grease traps, steam tunnels, pipe chases, and basements (especially near boilers or standing water). They may also survive winters in composting facilities or mulch piles. Decomposing organic matter of plant or animal origin is the preferred source of food, but other fresh foods and items such as natural fabrics are also eaten. These cockroaches are most commonly a problem in larger institutional buildings and food service facilities with access to lower levels of steam pipes and sewer outlets. They are the most common cockroach to be found in city sewer systems. Train tunnels and underground passageways are also avenues of movement for American cockroaches.

Aside from being an aesthetic nuisance, American cockroaches can carry disease organisms and contaminate food, stored products, food service areas, and sterile environments in hospitals.