This study examined timeliness, access, and intensity of outpatient medical service use in a national sample of veterans with comorbid medical disorders discharged from Veterans Affairs (VA) psychiatric units (N = 44,533). The factors that predicted decreased use of medical services included diagnosis of schizophrenia, posttraumatic stress disorder, and substance abuse. The factors associated with increased use of medical services included proximity to a VA outpatient clinic, receipt of VA compensation payments, discharge from a facility with greater resources devoted to medical-surgical care, and prompt outpatient mental health follow-up. Better integration of medical and psychiatric services may help improve access to medical care for the severely mentally ill.