To determine the relationship between the cumulative effect of sequential clomiphene citrate (CC) treatments in unexplained infertile women with intercycle and intracycle serum hormone changes. Patients who received CC 50 mg in the first cycle (group I, n=34) as ovulation induction and those who received CC 50 mg in the second consecutive cycle (group II, n=18) were compared. Basal (cycle days 2-5) and trigger day (the day that recombinant human chorionic gonadotropin is given) levels of gonadotropin and steroid hormones were measured. The 17OHP increase on trigger day was found to be statistically significantly higher in group II compared to the basal day (p=0.083). The testosterone (T) response on the trigger day of the patients in group II was found to be statistically significantly higher than that in group I (p=0.023). The number of selected follicles was negatively correlated with a follicle-stimulating hormone decrease and positively correlated with an estradiol increase. Endometrial thickness was positively correlated with a luteinizing hormone increase, and cycle cancelation was positively correlated with decreased estradiol. Based on this study, it was concluded that the reason for the increased efficiency rate in successive cycles of CC may be the cumulative increase in T and 17OHP levels. However, this result was found not to affect the clinical pregnancy rate.