Objective: Examination of the role of nuclear factor-kappa beta (NF-kB) expression in the etiopathogenesis of endometrial cancer, by means of the immunohistochemical method. Materials and Methods: Patients who applied to participate in the study at the clinic were grouped into three categories: those diagnosed with benign endometrial pathology, those with endometrial hyperplasia, and those with endometrial cancer. NF-kB analysis was conducted in the endometrial tissues of the patients’ paraffin blocks by means of the immunohistochemical method. For objective assessment purposes, the H score of each patient was calculated. SPSS 15.0 program was employed for statistical analysis. Results: The average H score of the first group, comprising benign endometrial pathologies, was 102.4 ± 85.9, that of the hyperplasia group was 143.6 ± 122.4, and that of the cancer group was 276.8 ± 61.8. The average values of groups 1 and 2 were similar (p = 0.349); however, the third group’s average H score was significantly higher (p < 0.001). Conclusion: NF-kB, which is a critical mediator in the inflammation process, might be related to the development of premalign and malign endometrial changes.