Adults are 1 to 1 1/4 inches long and shiny dark brown to black in color. Males have reduced wings that cover 75 percent of the abdomen; the females' wings are present but very reduced and functionless. This species cannot fly. Nymphs are dark reddish brown with very short cerci. The egg capsule is 3/8 inch and reddish brown when deposited but then turns black. There are usually 8 eggs on each side.

Females carry the egg capsule for just over a day and then deposit it or cement it in place. Eggs hatch after 60 days in cooler temperatures (shorter than other cockroaches) and from egg to adult can take up to 2 years. The reproductive potential for this species is not as great as German cockroaches. Oriental cockroaches, sometimes referred to as "water bugs" prefer humid or damp areas but cooler environments than preferred by American cockroaches. They are commonly found in sewers and most often in lower levels of buildings, compactor rooms, basements, and crawl spaces. They do not frequently enter living spaces or warm, dry upper floors, although they can travel through buildings on pipes. This species survives well outdoors and can be found in natural areas, such as in mulch and leaf litter and under stones and other debris.

A strong foul odor is produced by Oriental cockroaches. They are filthy and can cause general contamination of human environments. They may enter through floor drains, sewer pipes, or other openings in a building, but they may also enter through a door or window from the outdoor environment.