The number of sphincter-preserving operation for rectal cancer has been steadily increasing in the recent years due to QOL. More specifically, anterior resection using an autosuture instrument is increasing. Curability with this method is about the same compared to rectal amputation. Superlow anterior resection has been defined as anastomosis within 20 mm from the dentate line. This operation was performed on 42 cases. These 42 cases were compared with those undergoing other methods for different factors including distance from the anal edge of cancer to cut end (AW), gross morphology, lymph node metastasis, longer diameter of the tumor, the degree of circumference involved, and prognosis. We drew the following conclusions for indication of this superlow anterior resection for rectal cancer. 1. Dukes A needs a 20 mm distance from AW. 2. Dukes B needs a 30 mm distance from AW with less than half the circumference. 3. Dukes C needs a 40 mm distance from AW with less than half the circumference. 4. Negative EW. 5. Lateral lymph node metastasis and vessel permeation are not significant.