Adult male rats were fed diets containing 0, 5, 15, and 30 ppm chlordecone for 90 d and then either bred to untreated females or sacrificed for terminal studies. Chlordecone residues in liver, fat, and serum were determined in the treated males. Reproductive performance was unaffected, and no histologic changes in the male sex organs could be attributed to chlordecone treatment. Reversible decreases in the motility and viability of epididymal spermatozoa and decreased sperm reserves in the cauda epididymidis were observed in rats fed 15 or 30 ppm. No effect on sperm morphology or on sperm concentration in epididymal fluid was detected. Chlordecone accumulation in tissues was linearly related to dietary levels, with the highest chlordecone concentration occurring in the liver.