20 to 30 mm long
Oval, dorso-ventrally flat body. Sturdy, rather long legs, tibiae with rows of spiny bristles.
Fine, moniliform antennae that can be longer than the body.
Very short elytra and stumped wings in females, whereas they cover ¾ of the body in males.
The two short cerci at the end of the abdomen have tactile hairs that are highly sensitive to sounds and vibrations, and enable oriental cockroaches to run away at the slightest noise.
Dark brown to nearly black, more or less shiny.
The pronotum is generally darker than the thorax, and the legs are hued with reddish brown.