Goldfish were fed DDT for three weeks, then exposed to phenobarbital solution for one week to study the possibility of microsomal enzyme induction and therefore possibly enhanced insecticide excretion. Analysis of DDT, DDE and DDD were made at intervals up to six weeks. Forty percent of the DDT fed was incorporated during the feeding. It was recovered mainly as DDE (68 to 96%). Significant differences between pesticide levels of phenobarbital treated and control fish were not found.