Substance use disorders have serious negative consequences for severely mentally ill (SMI) adults, but many do not receive adequate substance abuse treatment. As part of a larger project on access barriers to substance abuse treatment for SMI clients, this qualitative study examined two potential client-level barriers to treatment: minimization of drug problems and perceived acceptability of drug use to reduce psychiatric symptoms. Open-ended interviews about drug use were conducted with 24 SMI adults with substance use problems. The majority of respondents identified drug use as a major problem in their lives. Respondents were aware of the impact of drugs on psychiatric symptoms, and most believed that the negative effects of drug use outweighed any short-term benefits. Nearly all respondents believed it was not acceptable for SMI adults to use drugs except marijuana. Contrary to findings in the literature that SMI adults deny or minimize drug problems, most respondents acknowledged the seriousness of their drug use, were aware of the negative effects of drug use on their psychiatric symptoms, and endorsed abstinence as the optimal treatment goal. These findings have implications for substance abuse treatment for SMI clients, particularly interventions that emphasize education about drug use as a way to increase motivation for treatment.