To assess whether primary care medical homes (PCMHs) are accurately identified for patients receiving care in a specialty mental health clinic within an integrated public delivery system. This study reviewed the electronic records of patients in a large urban mental health clinic. The study defined 'matching PCMH' if the same primary care clinic was listed in both the mental health and medical electronic records. This study designated all others as 'PCMH unknown.' This study assessed whether demographic factors predicted PCMH status using chi-square tests. Among 229 patients (66% male; mean age 49; 36% White, 30% Black, and 17% Asian), 72% had a matching PCMH. Sex, age, race, psychiatric diagnosis, and psychotropic medication use were not associated with matching PCMH. To improve care coordination and health outcomes for people with severe mental illness, greater efforts are needed to ensure the accurate designation of PCMHs in all mental health patient electronic records.