Cockroaches are flattened, brownish, fast-running insects, with long, slender antennae. There are three life stages: egg, nymph, and adult. The female cockroach produces small, brown, bean-shaped egg cases that are deposited in out-of-the-way places. Several nymphs emerge from each egg case (up to 40 with the German cockroach, 15-20 with other varieties). The nymphs resemble adults except that they are smaller and lack wings. The nymphs gradually become larger and inhabit the same places as the adults. Cockroaches are prolific breeders. Species such as the German cockroach are capable of producing several thousand offspring in less than a year.

Cockroaches do not live in centralized nests or colonies like ants, bees, and termites. However, cockroaches do congregate in distinct areas, in response to aggregating odors in their feces. The droppings appear as pepper-like specks in areas of current or former activity. The spotting is similar in appearance to that of bed bugs, but can usually be distinguished by location, or by other signs of infestation. (Cockroaches seldom congregate on beds in the manner of bed bugs.)                  

Cockroaches are more active at night than during the daytime. During the day, they generally remain hidden in cracks and other dark, secluded areas. At night, they leave their hiding places and search for food. Cockroaches will eat all human foods, plus many other items such as soap, toothpaste, glue, hair, excrement, and filth.

In order to eliminate cockroaches, it helps to know where they are hiding. Preferred locations include warm, dark, moist areas, especially in kitchens and bathrooms. However, depending on the species and extent of infestation, cockroaches may be found anywhere in the home.