Male fertility is affected by a variety of lifestyle habits that include tobacco use. A large population of Indian men is addicted to tobacco chewing. The Abstract of our study was to assess the relationship between tobacco chewing in these Indian men - who were part of an infertile couple and their sperm characteristics. Design: Retrospective study. Setting: Private infertility clinic. Patient(s): Six hundred thirty-eight male patients undergoing infertility evaluations were grouped according to the frequency of their tobacco chewing habit: mild (< 3 times/day, n = 177), moderate (3- 6 times/day, n = 264),and severe (>6 times/day, n = 197). Intervention(s): None. Main Outcome Measure(s): Sperm characteristics (concentration, motility, morphology, and viability). Result(s): Sperm concentration, percentage motility, morphology, and percentage viability were significantly higher in the mild group vs the moderate group and in the moderate group vs the severe group. The percentage of men with azoospermia rose with the level of addiction (1% , 3% , and 14% ) as did the percentage of men with oligoasthenoteratozoospermia (2% , 8% , and 29% ), although the differences were not statistically significant. Conclusion(s): In our study, use of chewing tobacco by a group of Indian men who were undergoing infertility evaluation was strongly associated with a decrease in sperm quality and to a lesser extent with oligoasthenozoospermia or azoospermia. Infertile men should be counseled about the adverse effects of tobacco chewing on sperm quality. A large population of Indian men is addicted to tobacco chewing. The Abstract of our study was to assess the relationship between tobacco chewing in these Indian men - who were part of an Design: Retrospective study. Setting: Private infertility clinic. Patient (s): Six hundred thirty-eight male patients undergoing infertility evaluations were grouped according to the frequency of their tobacco chewing habit: mild (<3 times / day, n = 177), moderate (3-6 times / day, n = 264), and severe (> 6 times / day, n = 197) Intervention (s) Sperm characteristics (percentage): Sperm concentration, percentage motility, morphology, and percentage viability were significantly higher in the mild group vs the moderate group and in the moderate group vs the severe group. The percentage of men w ith azoospermia rose with the level of addiction (1%, 3%, and 14%) as did the percentage of men with oligoasthenoteratozoospermia (2%, 8%, and 29%), although the differences were not statistically significant. Conclusion ): In our study, use of chewing tobacco by a group of Indian men who were undergoing infertility evaluation was strongly associated with a decrease in sperm quality and to a lesser extent with oligoasthenozoospermia or azoospermia. Infertile men should be counseled about the adverse effects of tobacco chewing on sperm quality.