Introduction: One of the earlier and most common drugs that have been used for ovulation induction is clomiphene citrate (CC), recently, other agents have been introduced to avoid the side effects of clomiphene citrate. Tamoxifen is another anti estrogenic compound that may be effective for ovulation induction in cases with thin endometrium. The aim of the study was to compare the efficacy of tamoxifen versus low dose clomiphene citrate for ovulation induction in cases with thin endometrium.  Patients and Methods: After the ethics committee approval, this randomized clinical study was conducted among 82 infertile women with thin endometrium (<7mm) and presented to the Gynecology outpatient clinic. The participants were divided randomly into two equal groups, seventy-eight women completed the study. Group A included 40 patients receiving tamoxifen while group B included 38 patients receiving clomiphene citrate (CC).
Results: Mean number of mature follicles ≥ 18 mm was 1.7 ± 0.6 in group A and 1.9 ± 0.8 in group B ; the difference was statistically insignificant (p-value = 0.2). Endometrial thickness (ET) was significantly different between both groups; it was higher in tamoxifen group than clomiphene citrate group (8.9 ± 1.2 mm versus 7.2 ± 1.1 mm, p < 0.0001). Also, it was noted that there were significant statistical discrepancies between both groups regarding pregnancy rate and ongoing pregnancy rate, as they were 22.5% and 17.5 % in group A and 5.3% and 2.6%, respectively, in group B (p<0.05). Conclusion: Tamoxifen has valuable effect on endometrial thickness, tamoxifen increases endometrial thickness and livebirth rate in patients with thin endometrium