PURPOSE: To evaluate the usefulness of endorectal surface coil magnetic resonance (MR) imaging in local staging of prostate carcinoma which is important to determine the method of therapy. MATERIALS AND METHODS: Endorectal surface coil prostate MR imaging was performed in 82 patients who received radical prostatectomy and comparatively analyzed with the pathologic findings. Multi-coil array technique with endorectal balloon coil and phased array coil in anterior pelvic wall was often applied. After localization with WARPSPGR Iocal izer (flip angle:30 degrees), the prostate images were acquired with FOV 10--12cm, 3--4mm slice thickness, 2 NEX, 256) < 128 matrix (fast spin echo=FSE:256X256, Echo train 16) by 1. 5T GE Signa. T1 and T2 weighted axial spin echo or FSE, with or without sagittal and/or coronal FSE were obtained. RESULTS: MR imaging using endorectal coil had 82% of (87% if 5 underestimated cases of microscopic capsular or seminal vesicular invasion are excluded) accuracy in the differentiation of intraprostatic carcinomas from those with extracapsular extension. In preoperative MR diagnosis of stage B carcinoma, the sensitivity was 79% and the specificity was 75%. CONCLUSION: MR imaging using endorectal surface coil with or without multi-coil array technique is considered to be the method of choice in the determination of the local extent of prostatic carcinoma.