The South Oaks Gambling Screen is a 20-item questionnaire based on DSM-III criteria for pathological gambling. It may be self-administered or administered by nonprofessional or professional interviewers. A total of 1,616 subjects were involved in its development: 867 patients with diagnoses of substance abuse and pathological gambling, 213 members of Gamblers Anonymous, 384 university students, and 152 hospital employees. Independent validation by family members and counselors was obtained for the calibration sample, and internal consistency and test-retest reliability were established. The instrument correlates well with the criteria of the revised version of DSM-III (DSM-III-R). It offers a convenient means to screen clinical populations of alcoholics and drug abusers, as well as general populations, for pathological gambling.