Questions about drug use and criminal behavior were asked subjects during an interview that lasted 30 to 60 minutes. Some similarities between sample types were found, but differences were more numerous. Notably, street respondents started cocaine at a younger age; had used crack regularly for a longer time; were more likely to have used pills, heroin, and freebase cocaine; were much more likely to be using crack (but only crack) on a daily basis; and were more likely to obtain crack by being paid in it, especially for drug dealing. Treatment respondents were more likely to use multiple forms of cocaine, to use cocaine in a binge pattern and with high per-day dosages, and to pay for cocaine with cash they got from a job. 5 tables, 1 figure, and 22 references