OBJECTIVE – To determine the incidence of endometrial hyperplasia in infertile women with PCOS . METHODS – Infertile women booked in Infertility clinic were screened for presence of PCOS aand these women underwent premenstrual endometrial biopsy . The incidence of endometrial hyperplasia was assessed in these women PARTICIPANTS A total of 2974 infertile women were consecutively screened and PCOS was found in 538 women Intervention : Endometrial biopsies were performed in all PCOS women and endometrial biopsies of 459 women were included in the analysis MAIN OUTCOME MEASURES AND RESULTS -The incidence of PCOS in the infertile women screened in the tertiary referral infertility clinic of North India was found to be 18%. Proliferative endometrium was reported in 58 % of these women .A total of 8.7 % women had endometrial hyperplasia detected, which included women with simple , complex, complex hyperplasia with atypia and adenocarcinoma. Simple hyperplasia without atypia was seen in 31 women ,complex hyperplasia without atypia was reported in 4 women ,complex hyperplasia with atypia was confirmed in 3 women and 2 cases of well differentiated adenocarcinoma of endometrium were confirmed after histopathology reporting . Oligomenorrhoea was present in 75% women detected with hyperplasia and had needed progesterone for withdrawal bleeding .Two PCOS women(1 with complex hyperplasia and 1 with adenocarcinoma ) had regular menstruation as they were on ovulation inducing drugs before visiting this hospital .Only 14 % of women detected with endometrial abnormality had abnormal uterine bleeding . Mean endometrial thickness was 9.2 mm in women with hyperplasia with or without atypia and malignancy . Mean age was 27.98±3.7 SD, where all women with complex hyperplasia with and without atypia and adenocarcinoma were less than 36 years of age . Conclusion : The incidence of endometrial hyperplasia in young PCOS women is not reported in literature . It is worthwhile to detect endometrial hyperplasia to prevent progression to atypia or malignancy by giving progesterone treatment . In women detected with atypia or malignancy treatment for regression has been reported to have favorable results .