A circular stapling apparatus was especially designed for use in low colorectal anastomoses. In shape and size it resembles a slightly oversized proctosigmoidoscope. After the tumor-bearing segment is resected in the standard manner, the instrument is introduced via the anus through the distal segment into the abdomen. The proximal and distal segments are apposed and mechanically anastomosed. A secure anastomosis is thus performed more quickly and more reliably than by standard suture methods. The method has been used successfully in 20 dogs, without evidence of leakage or stenosis. In 165 human operations for low rectal carcinoma performed in Russia from 1967 to 1972, the mortality was 2.4% and the leakage rate was 3.6%. No stenosis or late stricture occurred.