An epidemiologic study of multiple primary malignant neoplasms with endometrial cancer patients is presented. Coexistence of endometrial carcinoma with second primary malignant neoplasms was evaluated and controlled for age, residence, civil status, education, parity, menarche age, last menstruation age, length of reproductive period, blood group, hypertension, diabetes, body mass index, sterility, histological subtype, grading, staging.From 1984-1998 136 endometrial carcinomas have been evaluated in the Department of Gynecology & Obstetrics in Hospital of Słupsk retrospectively. All double and triple neoplasms have been histologically recorded, doubtful cases have been excluded.Of 136 endometrial carcinomas 16 (11.6%) were multiple malignant neoplasms. Of these neoplasms 9 (6.6%) occur together with breast cancer, 3 (2.2%) with ovarian carcinoma, 1 (0.7%) with stomach carcinoma, 1 (0.7%) with rectum carcinoma, 1 (0.7%) with carcinoma in focus of endometriosis and 1 (0.7%) coexists with double neoplasms (bowel and endometriosis carcinoma) During the 14-year period of study, 15 patients (11.0%) out of 136 patients diagnosed as having endometrial cancer had double and 1 (0.6%) had triple primary malignant neoplasms. There was not significant difference in age rate (p = 0.72), residence rate (p = 0.93), civil status rate (p = 0.76), education rate (p = 0.70), parity rate (p = 0.76), menarche age rate (p = 0.46), blood group rate (p = 0.45), hypertension rate (p = 0.94), diabetes rate (p = 1.0), not overweight status rate (BMI 32) rate (p = 0.03), last menstruation age rate (p = 0.04), length of reproductive period rate (p = 0.04) between both patients group (with and without second primary malignant neoplasma).Patients with endometrial cancer should be carefully and regularly followed up by monitoring et every anatomic site, especially the breast, stomach, and colon, in order that the development of a second primary carcinoma can be detected as early as possible, and not be overlooked in examinations. Additional risk factors for endometrial carcinoma with multiple malignant neoplasma include: menopause occurring after age fifty-one; obese women with body mass index (BMI) higher than 32; reproductive period longer than 37 years.