Alcoholics Anonymous (AA) participation has been measured in addiction research, but few validated tools distinguish components of this multidimensional construct. Data are derived from a sample of treatment-seeking alcoholics, and Service to Others in Sobriety validity and response stability is reported by using a test-retest sample. Findings demonstrated adequate psychometric properties of the Service to Others in Sobriety, including convergent validity, internal consistency (alpha = 0.92) and test-rest reliability (r = 0.94). The Service to Others in Sobriety is a valid measure of AA-related helping activities pertinent to the daily lives of recovering alcoholics. Tables, figure, and references (Published Abstract)