The organochlorine insecticide lindane (gamma-hexachlorocyclohexane) induces hepatomas in select strains of mice including two of three phenotypic classes of (YS x VY) F1 hybrid mice. In contrast, lindane does not induce hepatomas in rats and other strains of mice. It has been suggested that variations in the biotransformation of lindane may play a role in the different susceptibility of rodents to lindane-induced hepatomas. The study reports the effect of chronic treatment with 160 ppm dietary lindane on the comparative metabolism and disposition of this insecticide in obese yellow A(vy)/a, lean pseudoagouti A(vy)/a, and lean black a/a phenotypes of (YS x VY) F1 hybrid female mice at 17, 30, 56, and 86 weeks of age. Twenty four hours prior to necropsy, all mice were dosed p.o. with 18 mg lindane (containing 55 micro Ci (U-(14)C) lindane)/kg. Urine, feces, and expired air were sampled for analysis. Data indicated that metabolism of lindane and excretion of its metabolites by these mice differs significantly from that of rats which are resistant to lindane-induced hepatomas.