Abstract Field evaluations were conducted in single-family dwellings infested with at least 25 visible German cockroaches per kitchen to compare the efficacies of 2 concentrations of cypermethrin against a standard, chlorpyrifos. Visually-sighted German cockroaches were tallied, with flashlight illumination where necessary, in each kitchen prior to insecticide application. Items in cabinets were removed during the tally procedure to facilitate counting and to provide clear access for insecticide application. Counts were performed during Apr followed immediately by treatment with additional inspections and retreatments where living cockroaches were sighted at specified intervals. Cypermethrin (Demon) and chlorpyrifos (Dursban) sprays were applied according to label directions with a 3.8 liter, compressed air sprayer equipped with a “Multeejet™” nozzle using 1.4 kg/cm2 air pressure and pin stream spray pattern. Five replicates (single-family dwellings) were used per treatment. Other rooms were treated, but the number of cockroaches and quantity of spray applied were not recorded. Floor and wall surfaces of the kitchen were combined for the kitchen area (m2). Analyses were calculated on percentage reduction for each house using a general linear models procedure and the Waller-Duncan K-ratio t test for variables.