The effect of cigarette smoking on ovarian reserve as measured by basal serum follicle stimulating hormone (FSH) concentrations, and by the response to a standard ovarian stimulation protocol, was examined retrospectively in 173 consecutive women (108 non-smokers and 65 smokers) undergoing in-vitro fertilization (IVF) and embryo transfer treatment. Women who smoked had a higher mean basal serum FSH concentration (P < or = 0.0001), in particular younger (<36 years) women, and required a statistically significantly higher mean dosage of gonadotrophins for ovarian stimulation than the non-smokers (48.1 +/- 15.6 versus 38.9 +/- 13.6 ampoules, 75 IU/ampoule; P < 0.0001). A lower mean number of oocytes was obtained in smokers than non-smokers (6.2 +/- 3.4 versus 11.1 +/- 6.3, oocytes P < or = 0.0001) and the rate of abandoned cycles (18.5 versus 8.5%) and total fertilization failure (18.5 versus 8.5%) was higher. The clinical pregnancy rate per cycle in smokers was 16.9% versus 21.3% in non-smokers but this was not statistically significant. In conclusion, cigarette smoking in women appears to significantly reduce their ovarian reserve and lead to poor response to ovarian stimulation at an earlier age.