Background: Cyclin D1, a member of the cyclin protein family is instrumental in the cell cycle due to its influence on the progression from G1 to the S phase. Its overexpression causes reduced doubling time and is also associated with clonogenic growth. Aim of the study: The purpose of the present study was to assess cyclin D1 expression in patients with endometrial lesions. Methods: Prospective study in the department of pathology at A.C.S Medical College and Hospital on 210 patients with cyclin D1 marker was done. Results: Majority of the cases were endometrial hyperplasia without atypia constituting 21.4%, followed by Disordered proliferative endometrium occupying 20.4% , Secretory endometrium 17.7%, Atypical endometrial hyperplasia and Proliferative endometrium constituted 16.6% each, Endometrial carcinomas 7.1%. Among 15 cases of endometrial carcinomas, majority of carcinomas were of endometrioid type 66% (10/15) followed by adenosqamous 13.3% (2/15), serous papillary type of carcinomas 20% (3/15). Conclusion: Cyclin D1 expression is significantly higher in patients with endometrioid endometrial carcinoma. The extent of cyclin D1 expression is strongly correlated with nuclear and histological grade, myometrial invasion, lymphovascular invasion and lymph node invasion in patients with endometrioid endometrial carcinoma.