Chlorpyrifos, diazinon, and propoxur were tested for repellency and efficacy against German cockroaches, Blattella germanica (L.). Repellency of each material was determined by using a relative avoidance index (RAI) and was directly proportional to concentration. Avoidance to each toxicant decreased significantly and mortality increased in choice tests when an extract of aggregation pheromone (AP) was added. Chlorpyrifos (0.25% + AP) and diazinon (0.5% + AP) produced significantly higher mortality than any toxicant alone. In field control tests in apartments infested with German cockroaches, chlorpyrifos (0.5%) and Knox-Out® (1.0%) produced over 90% reductions within 4 wk, but diazinon (0.5%) and flowable microencapsulated diazinon (Knox-Out® 2 FM) (0.5%) failed to produce significant control within 2 wk after treatment; chlorpyrifos (0.25%) produced only partial control. However, similar concentrations of each material + AP produced 78.4, 82.0, and 90.7% reductions at 2 wk, respectively.