PURPOSE: To assess the accuracy of magnetic resonance (MR) imaging using an endorectal surface coil ineval-uation of local lesions of prostate carcinoma. MATERIALS AND METHODS: Twenty patients with surgically provenprostate carcinoma underwent MR imaging using a 1.5T unit and an endorectal surface coil made at the Asan MedicalCenter. T1-weighted images in the axial plane and T2-weighted images in the axial, coronal, and sagittal planeswere obtained in all patients. We divided the prostate gland into right and left lobe, then determined thelocation of carcinoma within it, as well as capsular penetration and seminal vesicle invasion. MR images werecompared with surgical specimens. RESULTS: MR imaging using an endorectal surface coil accurately demonstratedthe staging of prostate carcino-ma in 60% of patients (12/20), but with regard to the location of carcinoma withinthe prostate gland, capsular penetration, and seminal vesicle invasion, only nine cases (45%) showed completeagreement between en-dorectal surface coil MR images and pathologic findings. The accuracy of localizing thecarcinoma within the prostate gland, capsular penetration, and seminal vesicle invasion were 65%(13/20),70%(14/20), and 90%(18/20), respectively. CONCLUSION: MR imaging using an endorectal surface coil for thelocalization of prostate carcinoma and periprostatic tissue invasion showed a low degree of accuracy. Morespecific imaging findings are therefore needed.