To help inform the design of a self-management intervention for improving the physical health of adults with serious mental illnesses, we conducted focus groups about their perceived medical care and physical health needs. Adults with serious mental illnesses participated in four semi-structured focus groups conducted at a transitional living facility, a social club, and a Hispanic outpatient mental health clinic. Questions included their recent experiences of seeking medical care, the effect of having a mental illnesses diagnosis, strategies for active self-care, and perceived barriers to better physical health. In addition to various systemic barriers to better medical care, participants articulated limited knowledge and self-efficacy regarding active self-management of their physical health. Despite their interest in learning more about health promotion, most participants expressed a sense of personal futility and powerlessness in improving their health. These data suggest that any effort to improve the wellbeing of these adults will need to address self-efficacy in the hope of improving self-care for their physical health needs.