Objective To investigate the development and prognosis of peroxisome proliferators-activated receptor-γ(PPAR-γ) and cyclooxygenase-2(COX-2) in endometrial carcinoma. Methods The electron microscopic immunohistochemical technique was used to observe the ultrastructure location of COX-2 protein labeled by colloidal gold in the endometrial carcinoma. Results 1.There were negative immunohistochemical staining signals of PPAR-γ in both the normal endometrium and hyperplasia endometrium, whereas, was positive staining in the endometrial carcinoma; 2.The intensities of the COX-2 immunohistochemical staining were significantly statistical difference among the normal endometrium, the hyperplasia endometriu and the endometrial carcinoma(EM>P/EM><0.01); 3. The COX-2 labelled by colloidal gold granules was observed in the endoplasmic reticulum, nuclear membrane and nuclei in the endometrial carcinoma. Conclusion Both PPAR-γ and the COX-2 might play an important role in the development