Data were obtained for a sample of 620 youth between July 1988 and June 1989. Physicians in training at the Childrens Hospital of Los Angeles conducted examinations and interviews using a psychosocial risk assessment instrument. This instrument covered six significant areas: home, education, activities, drug use and abuse, sexual behavior, suicidality and depression, and satanic ritual involvement. Of the 620 youth, 153 or 25 percent revealed they were involved in prostitution at the time of the visit. Youth involved in prostitution were more likely than those not involved to be female, older, and white. Most youth involved in prostitution came from outside Los Angeles County, and 40.1 percent were from outside California. Youth involved in prostitution comprised only 25 percent of the sample population, but accounted for 37 percent of recorded medical diagnoses. Involved youth were more likely to have dropped out of school and were more than five times as likely to report homosexual or bisexual identities. In general, study results demonstrated that homeless youth involved in prostitution were at greater risk for a wide variety of medical problems and health-compromising behaviors including drug abuse, suicide, and depression. Implications of the findings for public health and social policy are discussed. 7 references and 3 tables