Endometrial cancer is a common gynecological cancer that occurs frequently in perimenopausal and postmenopausal women. Several factors influence the incidence of endometrial cancer, such as age, family history of cancer, Body Mass Index, parity, diabetes mellitus, age at menarche, menopausal status, and age at first birth. This study aims to determine the risk factors associated with endometrial cancer in Dr. Soetomos hospital in Surabaya. This research uses an analytical observational design with a case-control approach. The subjects were chosen by convenience sampling, and 70 patients in the case group and 69 in the control group were obtained. Bivariate analysis using Mann-Whitney and Chi-square, then multivariate analysis using the logistic regression test with significance p<0.05. The results showed that age, family history of cancer, diabetes mellitus, menopausal status, and age at first birth were related to endometrial cancer. Body mass index, parity, and age at menarche are variables not associated with endometrial cancer. Diabetes mellitus is the most dominant factor in increasing endometrial cancer incidence with Odd Ratio (OR)= 7.085 (95% CI 1.299-38.637). This research provides information about what factors are related to and influence the incidence of endometrial cancer. The development of these findings needs to be carried out in a larger sample size and using a cohort study.