The study reports the effects of acute and chronic Cd treatment on the metabolism of lindane by rats 3 days, 1, 2, 3, and 5 weeks after exposure to the heavy metal. Eighty adult male Wistar rats were randomly assigned to one of four exposure groups. One group was injected sc, three times a week throughout the study, with 0.75 mg of Cd/kg body weight. The other three groups received one sc injection of either 0, 1.04, or 3.20 mg of Cd/kg body weight. Twenty-four hours prior to sacrifice four rats from each group received a po dose of 1.83 mg of lindane (containing 2.5 microCi of (14C)lindane). Results of this study indicate that Cd pretreatment causes inhibition of lindane metabolism which is of long duration and which is not appreciably relieved by chronic exposure to the metal.