Background: Polycystic ovary syndrome (PCOS) is defined as the presence of oligo-anovulation and/or hyperandrogenism proven by clinical or laboratory findings and/or polycystic ovary image on ultrasonography. It affects 5-10% of women in the reproductive period and is the most common cause of anovulatory infertility. This study was conducted to identify the efficacy between letrozole versus clomiphene citrate as ovulation induction drug in infertile polycystic ovary syndrome women. Methods: This retrospective study was conducted in Bankura Sammilani Medical College and Hospital among 98 infertile PCOS pts of 20-35 yrs of age which were selected from outpatient department of Bankura Sammilani Medical College & Hospital after applying inclusion and exclusion criteria and after that data was collected. Statistical data were analysed by using Microsoft Excel and SPSS V.20 software. Results: Most of the participants of Clomiphene citrate i.e. 53.06% (26) out of 49 belongs to 26 - 29 yrs. of age group. Most of the participants of Clomiphene citrate i.e. 46.94% (23) out of 49 BMI was within normal level. Most of the participant of Clomiphene citrate i.e. 67.35% (33) out of 49 was amenorrhea, whereas 8.16% (4) participants didn’t have any problem. Mean value of duration of infertility of participants of Clomiphene citrate group was 3.23, in case of Letrozole group of participants it was 3.20. Most of the participants of Letrozole i.e 75.51% (37) out of 49 ovulation was happened, whereas 24.49% (12) participants ovulation was not happened. Most of the participants of Clomiphene citrate i.e. 75.51% (37) out of 49 was multifollicular, whereas 4.08% (2) participants didn’t have any follicle. Participants of Clomiphene citrate i.e. 89.79% (44) out of 49 UPT result was negative, whereas 10.20% (5) participants result was positive. Conclusions: Compared with CC, its use is associated with thicker endometrium, good ovulation rate and considerable number of pregnancies. So, Clomiphene citrate easily replaced by Letrozole nowadays.