The progesterone receptor gene (PROGINS) has been identified as a risk modifier for benign and malignant gynecological diseases. The present case-control study is to evaluate the role of the PROGINS polymorphisms, as risk factor, for endometrial cancer development and to investigate the association between these genetics variants and clinical/pathologic variables of endometrial cancer. PROGINS polymorphism was examined in a total of 121 patients with endometrial cancer and 282 population-based control subjects, all located at the same area in São Paulo, SP, Brazil. The genotyping of PROGINS polymorphism was determined by polymerase chain reaction. The frequencies of PROGINS polymorphism T1/T1, T1/T2, and T2/T2 were 82.6%, 14.9%, and 2.5% in the endometrial cancer patients and 78.4%, 21.6%, and 0% in the controls, respectively. The chi(2) test showed a higher incidence of the T2/T2 genotype in the endometrial cancer group subjects, these results were statistically different (P= 0.012). However, due to the fact that there were no women in the control group showing homozygosis for the allele T2, the correct evaluation of odds ratio could not be properly calculated. Regarding the clinical and pathologic findings observed within the group of patients with endometrial cancer, there was significant correlation between T1/T2 genotype and the presence of myoma (P= 0.048). No correlations were observed among the other variables. These data suggest that the PROGINS polymorphism T2/T2 genotype might be associated with an increased risk of endometrial cancer.