German cockroach females, unlike most other roaches, carry the egg capsule protruding from their abdomen until the eggs are ready to hatch. The case is then dropped in a secluded location, with the nymphs emerging within one day. A female may produce four to eight cases during her lifetime, each containing 30 to 48 eggs. Eggs hatch in about one month, and nymphs develop in 1-1/2 to 4 months. Female roaches live about 6-1/2 months and males live slightly less. The German cockroach produces more eggs and has more generations per year (three to four) than other roaches, and only a few individuals are needed to develop into troublesome infestations. This roach is spread by commerce and transportation as well as mass migrations. It is the most prevalent pest in low income apartments in the United States.

During the day, these roaches may be found hiding, clustered behind baseboard molding, in cracks around cabinets, closets or pantries, and in and under stoves, refrigerators and dish washers. If clusters of roaches are seen during the day, the population is large. Both nymphs and adults are very active and capable of running rapidly. German cockroaches have a high need for moisture and usually travel 10 to 12 feet from their harborage for food and water in kitchens, bathrooms, utility rooms, etc., preferring darkness. Without food or water, adults may die in two weeks, but can live a month with only water.