Dyslipidemia and diabetes mellitus are commonly coincident, and together contribute to the development of atherosclerotic disease. Medication therapy is the mainstay of treatment for dyslipidemia. Optimal medication therapy for dyslipidemia in patients with diabetes reduces cardiovascular events but necessitates patients take multiple medications. As a result, sub-optimal adherence to medication therapy is common. Factors contributing to medication non-adherence in patients taking multiple medications are complex and can be grouped into patient-, social and economic-, medication therapy-, and health provider and health system-related factors. Strategies aimed at improving medication adherence may target the patient, health care providers, or health systems. Recent data suggest medication non-adherence contributes to racial health disparities. In addition, health literacy, cost-related medication non-adherence, and patient beliefs regarding medication therapy have all been recently described as factors affecting medication adherence. Data from within the last year support an important role for regular contact between patients and health care providers to effectively address these factors. Cost-related barriers to medication adherence have recently been addressed through examination of health system approaches to decreasing cost-related non-adherence.