Cardiovascular disease is the leading cause of death in Type 2 diabetes, which commonly occurs in patients with serious mental illnesses (SMIs). We determined the extent to which patients with diabetes and SMI, relative to diabetes patients without SMI, met American Diabetes Association goals for cholesterol and blood pressure, met criteria for the metabolic syndrome, and were prescribed medications known to reduce cardiovascular events. We found that less than half of diabetes patients, both with and without SMI, met recommended goals for cholesterol levels; even fewer had adequate blood pressure control. In addition, a substantial proportion of all diabetes patients met metabolic syndrome criteria. However, diabetes patients with SMI were less likely to be prescribed cholesterol-lowering statin medications, angiotensin-converting enzyme inhibitors, and angiotensin receptor blocking agents than diabetes patients without SMI. Patients with both diabetes and SMI are treated less aggressively for high cardiovascular risk than diabetes patients without mental disorders.