Ambulatory-care teaching programs have been traditionally based in hospital settings. As many patients, in particular the homeless and underinsured, have never reached these settings, we describe a nontraditional outreach health-care program for medical residents. This multidisciplinary program places medical residents on a mobile van to deliver care to a population in New Haven where 18.2% of its families are below the poverty level and have limited or no access to health care at the teaching hospital. On-site urgent care is given along with HIV, pregnancy testing, and blood pressure screening. Health-care follow-up, dental care, alcohol detoxification, and drug counseling are scheduled. A total of 764 adult patients were seen between November 1991 and June 1993 by PGY2 residents on ambulatory rotations. One hundred forty-one patients consented to respond to a questionnaire. Thirty-seven (26%) were homeless with a mean length of homelessness of 15 months. Forty-one percent had been victimized within one year and 33% currently used illicit drugs. The benefits of this unique ambulatory teaching program for medical residents are described.