Indiana University-Purdue University Indianapolis (IUPUI) / People with severe mental illness (SMI) often suffer from comorbid physical conditions that result in chronic morbidity and early mortality. Physical health decision-making is one area that has been largely unexplored with the SMI population. This study aimed to identify what factors contribute to the physical healthcare decision-making autonomy preferences of persons with SMI, and to identify the impact of these autonomy preferences on medication adherence. Ninety-five adults with SMI were recruited from an integrated care clinic located in a community mental health center. Fifty-six completed a three-month follow-up. Multiple linear regression for hypothesis 1 (n=95) and hierarchical regression for hypothesis 2 (n=56) were used to analyze data on personal characteristics, physical health decision-making autonomy preferences and medication adherence. For the open-ended questions, thematic analysis was used to uncover facilitators and barriers to medication adherence. With this sample, being male predicted greater desired autonomy, and having less social support predicted less desired autonomy. When background characteristics were held constant, autonomy preferences and perceived autonomy support from the physician only contributed an additional 1% of the variance in medication adherence. Lastly, participants reported behavioral factors and having family/personal support to take medications as facilitators to medication adherence for physical health care, while citing financial and other resource limitations as barriers.