The aim of this study is the evaluation of the effect of clomiphen& tamoxifen in pregnancy rate. The inclusion criteria are infertile women with ovulatory dysfunction without any other causes. The exclusion criteria are: abnormal semen analysis and HSG or laparoscopy , age over 40, myoma, hyperprolactinema, FSH over12, hypothyroidism, hyperthyroidism, previous history of induction of ovulation, renal & liver disease and contraindication of clomiphen citrate and tamoxifen. The study population are 144 infertile women with ovulatory dysfunction who refered to infertility clinic of Alzahra hospital, after giving informed constant they randomized into two groups half of patients received tamoxifen 2 tab daily(40mg) for 5 day and the other half clomiphen 3 tab daily for 5 day from day 3-7 of menstrual cycle. Serial sonography for determination of endometrial thickness and pattern and number of dominant follicle was done. 5000 unit hcg after receiving at least one follicle ≥18mm injected and then the patients compared to gather from the points of pregnancy rate and side effects.