Individuals with severe mental illness (SMI) are at risk for inadequate general medical and preventive care, but little is known about their visits for primary care. We performed a cross-sectional analysis of primary care physician visits from the National Ambulatory Medical Care Survey (NAMCS) 1993-1998 and compared visit characteristics for patients with and without SMI. SMI was defined from ICD-9 diagnoses and medications. Primary care visits for patients with SMI were more likely to be return visits, were longer, and were more likely to have scheduled follow-up than for patients without SMI. Obesity, diabetes, and smoking were reported approximately twice as frequently in visits for patients with SMI compared to patients without SMI. The percent of visits with preventive counseling and counseling targeted at chronic medical conditions was similar for both groups. Likely appropriate to their complex needs, patients with SMI using primary care tend to have more return visits, longer time with the physician and are more often scheduled for follow-up care; their preventive counseling appears similar to non-SMI visits.