Forty patients with locally extensive carcinoma of the anorectum were treated by a combination of external and interstitial irradiation from April 1, 1974 to January 30, 1979. Twenty‐eight patients (70%) achieved complete local tumor control and two more patients with residual tumor were salvaged by surgery. Twenty‐four patients remain alive with local control for an average follow up period of three years. The overall complication rate has been 20%. Cancer 50:1746‐1750, 1982.