The sterile-insect release method was used to suppress a wild Mediterranean fruit fly, Ceratitis capitata (Wiedemann), population in a nonisolated area (13 km2) of Kula, Maui, Hawaii. From December 1981 to June 1982, an average of 4 million irradiated flies was released by air and ground each week. Three sets of data assessed the sterile-fly release program: adult trap catches, adult yield from collected fruit, and percent egg hatch. By each of these three criteria, a significant reduction of C. capitata occurred in the treated area compared with the control area. Average number of adults caught per trap per day was reduced from 1.4 to 0.5; average number of C. capitata adults per fruit collected declined from 3.0 to 0.6, and average percent egg hatch dropped from 85.5 (control) to 13.5% (treated). Results showed that the laboratory strain of C. capitata is highly competitive in the field.