Objectives: To compare the effects of clomiphene citrate with conjugated equine estrogen (early or beginning day 2 of menses vs. late or beginning day 7 of menses) and clomiphene citrate alone on endometrial thickness and pattern (i.e. trilaminar or non-trilaminar) among patients for induction of ovulation. Study Design: Prospective, randomized Setting: tertiary care hospital Inclusion criteria: Women aged 25-40 years old with infertility of at least 2 years duration who are candidates for ovulation induction. Exclusion criteria: Women on hormonal treatment 1 month prior to ovulation, with ovarian cysts, mullerian abnormalities, myomas or uterine cavity abnormalities. Results: Fifty-four women were included in the study with mean age 31.093 years +/- 4.655 (range 21 to 40 years), duration of infertility 4.954 +/- 3.228 (range 2 to 20 years), and day of the cycle when dominant follicle was noted was 11.907 +/- 1.751 (range of 8 to 16 days). Mean endometrial thickness was 0.960 cm in group I, 1.053 cm in group II and 0.850 cm in group III with a p value of 0.040625. There was significant improvement in thickness from baseline with a p value of 0.015166. There was no significant effect on endometrial pattern (p value = 0.236146). Conclusion: The addition of conjugated equine estrogens in ovulation induction with clomiphene citrate improves endometrial thickness.