Purpose: The purpose of this study was to review the effect of age and body mass index (BMI) on the prognosis, demographic characteristics, and pathological features of patients diagnosed with endometrial cancer, specifically before menopause. Materials and Methods: Patients that were diagnosed with endometrial cancer before menopause, were screened retrospectively. Between 1999 and 2011, 163 patients were identified while 40 were excluded. Patients were classified into three groups according to age (under 40 years, between 40-45 years, more than 45 years) and BMI (normal weight group, overweight group, and obese weight group). Demographical characteristics, histopathological features (Stage, grade and histology of the tumor, the presence of myometrial and/or lymphovascular invasion, history of diabetes mellitus, history of hypertension, hormonal contraception method, smoking, parity, infertility, family history, and recurrences) and survival rates were compared among the groups. Results: In total, 123 patients with a mean of 65.0 months follow up were enrolled into the study. The majority of the patients had endometrioid type in all age-related subgroups. Advanced stage endometrium cancer (Stage 2 and greater) was seen more commonly in the group of patient over 45 years of age against the other age-related subgroups (27.9% vs. 8% vs. 3.3%). Ratio of myometrial invasion more than 50% and occurrence of well-differentiated tumor were seen with a similar ratio among the age-related subgroups. Ratio of nulliparity and infertility were found statistically significant in the group of patients under 45 years of age against the group of patients over 45 years of age (p = 0.001,p = 0.03). The five-year estimated disease-free survival rates of women under 40 years of, women with an age between 40-45 years, and women over the age of 45 years were calculated as 73%, 95%, and 87%, respectively (p = 0.152). Concerning the histopathological features, there were no statistical differences between weight related subgroups. Comorbid conditions (hypertension and diabetes mellitus) were found as statistically high in the obese patients' group (43.5%-25.8%). In contrast to comorbid conditions, nulliparity and infertility histories were observed more often within the normal weight group (55.6%-38.5%). Mean disease-free survival time was calculated as 155.81 months in the normal weight group; 114.691 months in the overweight group, and 144.677 months in the obese group. Five-year disease-free survival rate was calculated as 91%, 81%, and 87%, respectively (p = 0.452). Conclusion: Women with premenopausal cancers generally exhibit early and favorable histopathological symptoms. Although advanced stage endometrium cancer incidence was detected to be higher in the premenopausal endometrium cancer patients aged above 45 years compared to other age subgroups. A significant difference in terms of survival rates between these groups was not reached. In the same manner, the authors did not find a significant difference in survival rates among different weight subgroups of premenopausal endometrium cancer patients. As a secondary result, the authors discovered that diabetes mellitus and hypertension play a key role in patients with a BM above 30 kg/m(2) and nulliparity and infertility play a key role in patients with a BMI below 25 kg/m2 in the development of premenopausal endometrial cancer.