Questions have been raised about voluntarism effects in personality research among heroin addicts. Heroin addicts volunteering for treatment tend to yield more elevated group Minnesota Multiphasic Personality Inventory profiles than heroin addicts who do not volunteer. Such observations have occurred primarily with white samples, however. The present study extended the test of the voluntarism hypothesis to black heroin users, comparing 157 volunteers with 27 nonvolunteers. As hypothesized, black volunteers differed significantly, scoring higher on the Hypochondriasis, Depression, and Hysteria scales. Such differences add evidence against the addiction-prone personality hypothesis and underscore the need for evaluating the effects of voluntarism and ethnicity in personality research on drug abuse.