Tumor-associated macrophages (TAMs) are derived from monocytes and recruited to the tumor microenvironment, where they play an important role in the progression of cancer. There is strong evidence for an inverse relationship between TAM density and clinical prognosis in solid tumors of the breast, prostate, ovary, and cervix. However, the role of TAMs in endometrial cancer is not well described. The objectives of this study were to determine whether macrophage distribution or density differed among normal endometrial tissue, hyperplasia, Type I, and II endometrial adenocarcinomas. In addition, we looked for a correlation among TAM density, known histopathologic prognostic indicators, and endometrial cancer progression. The pathologic specimens of women who underwent hysterectomy for benign disorders, endometrial hyperplasia, Type I, or Type II cancers were sectioned and stained with anti-CD68 antibody. The density of CD68 macrophages was quantified and stratified according to their epithelial or stromal location. Type I and II endometrial carcinomas had significantly higher macrophage density in both epithelial and stromal compartments than benign endometrium. In both benign and neoplastic specimens, the numbers of macrophages were significantly higher in the stroma compared with the epithelium. Although there were important trends in the density of TAMs with regard to several histopathologic prognostic indicators of endometrial cancer, none were statistically significant and the patients' cancer progression did not correlate significantly with the number of TAMs.