The results suggest that normative substance abuse patterns of male prostitutes are often characterized by daily polysubstance use involving some combination of alcohol, marijuana, and cocaine. The data indicate that increased quantity and frequency of substance use is associated with a higher degree of economic dependence on prostitution and a tendency to spend money earned on alcohol and drugs before purchasing other goods and services. Several social psychological cofactors, including self-identification as heterosexuals and negative attitudes toward homosexuals, are strongly associated with substance use during prostitution. Male prostitutes exhibiting symptoms of psychological distress, in particular obsession compulsion, personal inadequacy and inferiority, anxiety, and depression, are more likely to use drugs while engaging in prostitution than those experiencing milder or fewer symptoms of distress. Intervention programs for this population will need to focus on issues including self-esteem and psychological distress. 2 tables, 1 figure, and 32 references