Eight terpenoid derivatives with juvenile hormone activity were tested for teratogenicity. Three of the derivatives were teratogenic when administered to mice as a single intraperitoneal injection of 1 mg/gm on either day 9 or day 10 of pregnancy. However, intubation at 5 mg/gm of the two most teratogenic derivatives resulted in one of the derivatives marginally increasing the incidence of abnormal embryos above peanut oil-intubated controls; the other intubated derivative was without adverse affect. Of the remaining five compounds, two with high juvenile hormone activity were without teratogenic effect when injected at 1 mg/gm. Since teratogenic effects were observed only at a dose above likely exposure levels and by a route of administration not possible in the environment, support is provided for the potential use of terpenoid derivatives in the control of insect pests.