PURPOSE: In patients with endometrial carcinoma, preoperative knowledge of myometrial tumor extension has important prognostic and therapeutic implications. The purpose of th is study was to assess the usefulness of meg netic resonance (MR) imaging in preoperative evaluation of myometrial invasion of early stage endometrial ca rcinoma. MATERIALS AND METHODS: MR imaging findings of 31 consecutive patients with histologicallproved endometrial carcinoma, were prospectively analyzed and compared with pathologic results. Uyometrial invasion was classified into three groups; absence of myometrial invasion, superficial and deep invasion in accordance with clinical stage IA, lB, IC respectively. RESULTS: MR imaging had an accuracy of 74.2%, a sensitivity of 85.7%, and a specificity of 70.8% in stage IA (n=7); 67.7%, 46.2%, 83.3% in stage lB (n=l 3); 93.5%, 81.8%, 100% in stage IC (n=11) respectively. Overall accuracy was 79.9%. Nine of ten incorrect cases were underestimated, and one was overestimated. Degree of invasiveness was underestimated in cases with adenomyosis, small tumor showing focal wall thickening, and faint junctional zone in postmenopausal women. CONCLUSION: The results of this study show that MR imaging can be used to distinguish superficial and deep penetration of myometrium in endometrial carcinome.