Persons with serious mental illnesses have shorter life spans than the general population, and their earlier death is often related to cardiovascular disease. This study examined health literacy and cardiovascular medication adherence in a sample of 98 participants with serious mental illness. Sixty-two percent of the participants had adequate health literacy as measured by the Test of Functional Health Literacy in Adults. The association between health literacy and medication adherence was not significant after controlling for education. There was a significant association between health literacy and education level, health literacy and site, and health literacy and the sodium intake subscale of the Hill-Bone adherence scale.