OBJECTIVE: People with serious mental illness have higher mortality rates than the general population, and this difference is not explained by such causes as suicide or accidents. This study therefore examined access and barriers to medical care among persons with serious mental illness. METHODS: Using a nationally representative sample, the authors examined access and barriers to medical care among individuals reporting psychotic and mood disorders. The National Health Interview Survey (NHIS) and NHIS-Disability Component for 1994 and 1995 were merged to provide a sample of 156,475 people over age 18. Individuals with psychotic disorders, bipolar disorder, or major depression were compared with persons without mental disorders on the following outcomes: having a primary care physician, being unable to get needed medical care, being unable to get a needed prescription medication, and delaying medical care because of cost. RESULTS: Persons with psychotic disorders (odds ratio [OR]=.55, 95% confidence interval [CI]=.44-.69) and bipolar disorder (OR=.74, CI=.56-.98) had significantly reduced odds of having a primary care physician compared with people without mental disorders. For any barriers to care, persons with psychotic disorders, bipolar disorder, or major depressive disorder had greatly increased odds (ORs=2.5-7.0) of reporting difficulties in accessing care. CONCLUSIONS: Persons with psychotic disorders and bipolar disorder reported markedly more difficulty in obtaining a primary care physician and greater barriers to care than the general population. Interventions are needed to improve provision of primary medical care to this population.