Personality differences of 71 residents in a therapeutic community drug abuse program were examined with the Minnesota Multiphasic Personality Inventory (MMPI). Successfully treated males scored significantly (p<.05) higher on scales of Hypochondriasis (Hs), Hysteria (Hy), and Masculinity-Femininity (Mf). Successfully treated females obtained a significantly (p<.05) higher score on the Social Introversion (Si) scale. Unsuccessfully treated females scored significantly (p<.05) higher than the successfully treated females on the Masculinity-Femininity (Mf) scales. Of the two-point code types, all of the 49-94 code types were unsuccessful; the largest number of successfully treated drug abusers for any one code type was in the 48-84 code type.