Endometrial cancer is the most commonly diagnosed malignant disorder of the reproductive system in women and a disease of a highly developed, wealthy society, whose incidence and specific mortality tend to grow rapidly due to the global obesity epidemic, physical inactivity and population aging. The aim of this study was to determine the risk factors that affect the development of endometrial cancer in women in the Republic of Croatia. From a sample of one hundred patients treated at the Clinic for Women's Diseases and Obstetrics of the University Hospital Center Zagreb in 2016 due to suspected endometrial cancer, based on anamnestic data from medical records, we collected data and statistically processed them. Results showed that the average age of diagnosis of endometrial cancer is in the postmenopausal age, which corresponds to the data established so far throughout the literature. Reproductive factors such as the number of partity and the age of the last menstruation did not show a significant influence on the development of endometrial cancer. More than half of the respondents had a positive family history of cancer. Conditions of increased exposure to unopposed estrogen for instance overweight with associated comorbidities of which the most significant are hypertension and diabetes mellitus stand out as an important risk factor in the etiology of endometrial cancer. The average BMI of the respondents is 30.94 kg/m2. In conclusion, variable risk factors, which are characteristics of lifestyle, and include body weight and related diseases as well as physical inactivity, significantly affect the development of endometrial cancer. Lifestyle interventions would contribute to the prevention, earlier detection and more successful treatment of endometrial cancer.