In a random sample of 203 street youths recruited in the Haight-Ashbury neighborhood of San Francisco, the authors found significant differences between those who reported that they could go home if they wanted to compared to those who perceived that they could not go back home. Those who could not go home were significantly more likely to report having been away from home for more than 3 years, having run away before age 13, having been kicked out of their home, and not being in touch with their parents compared to the other group. Those who could not go home reported significantly more-injection drug use, which puts them at high risk for HIV. Health care providers can identify street youths at highest risk by asking the question "Could you go back home today if you wanted to do so?"