1. Carbofuran was administered orally to adult male rats at dose levels of 0.1, 0.2, 0.4 or 0.8 mg kg-1 body weight, 5 d wk-1 for 60 days. A dose dependent decrease was observed in body weight of rats treated with 0.2-0.8 mg carbofuran kg-1 body weight. 2. A significant decrease in the weight of epididymides, seminal vesicles, ventral prostate and coagulating glands was observed at various test doses of carbofuran except at the lowest dose. 3. Decreased sperm motility, reduced epididymal sperm count along with increased morphological abnormalities in head, neck and tail regions of spermatozoa were observed in rats exposed to 0.2, 0.4, or 0.8 mg carbofuran kg-1 body weight. 4. In addition, significant alterations were observed in the activities of marker testicular enzymes viz. sorbitol dehydrogenase (SDH), glucose-6-P-dehydrogenase (G6PDH) (decreased), lactate dehydrogenase (LDH) and gamma-glutamyl transpeptidase (gamma-GT) (increased) depending on dose. 5. Histologically, the results indicated the toxicity of carbofuran on testes depending on dose. The changes predominantly consisted of moderate oedema, congestion, damage to Sertoli cells and germ cells, along with the accumulation of cellular debris and presence of giant cells in the lumen of a few seminiferous tubules which showed disturbed spermatogenesis with the higher doses of carbofuran. 6. These observations determined a no effect level dose of 0.1 mg kg-1 body weight of carbofuran on the biochemical and morphological indices studied for male reproductive toxicity assessment in the rat model. The results of the present study provide first hand information on the reproductive toxicity of carbofuran in male rats.