To date, with drug users entering boot camps in increasing numbers, there are no theoretical studies of persons entering boot camps. This investigation is the first theoretical study of young persons in boot camp with a focus on the importance of religiosity in the processes leading to illicit drug use among first-admissions to the correctional system for adults. The study consisted of 326 males, age 15 to 24, from 25 classes in the only boot camp in Arkansas. The findings indicate that religiosity, like secular beliefs, had a negative reciprocal relationship to association with peers who engaged in unlawful behavior. Religiosity is a major influence leading to use of drugs, although an indirect influence. Religiosity, beliefs, attachment to caregivers, and abuse were factors that helped explain why some youths differentially associated with peers who were involved in illicit acts. The findings offer support to the underlying assumption of the investigation that religiosity is a significant factor in the processes leading to illicit drug use among first-admissions to correctional system for adults. Figures, tables, and references