Reported rates of mental illness and substance abuse in homeless populations vary widely and are usually based on clinical impressions. In this report structured interviews and objective measures of pathology were used to survey demographics, psychopathology, and substance abuse in a homeless population. Subjects (N=107), who were recruited from a soup kitchen meal line, completed a 46-item structured demographic questionnaire; a 39-item structured questionnaire on alcohol use, drug use, and their effects; a brief screening test of impairment; and the Minnesota Multiphasic Personality Inventory 168. The survey results indicated that the population was relatively young, male, and Caucasian. Serious alcohol abuse was indicated in about one-third of the cases, and serious street drug abuse was indicated in about one quarter. Severe psychopathology of psychotic proportions was found in over one-third of the cases. In contrast to these findings, few of the respondents perceived themselves as having emotional or substance abuse problems, and few rated themselves as unhealthy or in need of medication. This finding suggests that these people would be unlikely to seek help from mental health or substance abuse agencies. (NRB)