Fifty-four patients with primary carcinoma of the cervix were examined by magnetic resonance imaging (MRI). Different pulse sequences with T1 and T2 weighting were employed to determine optimum tissue contrast. The tumor had a uniform signal intensity similar to the myometrium on the T1 weighted image. In contrast, the tumor signal intensity increased on the T2 weighted image. In our series the primary tumor was clearly defined in nine of twenty patients with stage 0 and I disease and thirty-three of thirty-four patients with stage II, III and IV disease. In addition, the primary tumor was clearly defined in four patients who had unsatisfactory colposcopic findings (UCF). Parametrial invasion of the tumor was well depicted on transverse planes in four of twelve sides with stage IIb disease and twenty-eight of thirty-four sides with stage III and IV disease. T1 weighted images provided excellent tissue contrast between the high signal from pelvic fat and the low intensity of tumor tissue enabling demonstration of involvement of the pelvic side wall. Vaginal invasion was also clearly seen on T2 weighted sagittal images in seventeen of twenty-six patients. In conclusion, MRI is not only useful but is also a non-invasive method of detecting primary tumor and extra-uterine extension of cervical carcinoma.