A modified version of Feagin’s Intrinsic/Extrinsic Scale was found to be useful in determining the level of spirituality in adolescents in a drug free residential therapeutic community. This spirituality measure was found to have acceptable reliability. Evidence in support of its validity was demonstrated by the pattern of significant relationships obtained between spiritual orientation and spiritual-related beliefs (perceived connectedness to others) as well as behaviors (frequency of attendance at religious services as a child and frequency of engaging in prayer/mediation). One of the more interesting results found in the study was the widespread use of marijuana in the sample adolescents. Proneness to marijuana use appears to consist of many factors, one of which is less religiosity. Youths who had reported a greater cumulative lifetime history of marijuana use were less spiritually oriented than were their peers who had used marijuana less frequently. This finding is inconsistent with the previously held belief that intoxication is related to mystical states of being. The assessment of orientation to spirituality and its impact on substance-abuse treatment in adolescent has important differences from adults. Adolescents treatment needs may be vastly different from those of adults, and traditional forms of substance-abuse treatment may not be appropriate. Data were collected from 181 adolescents within 3 sites of a drug-free residential therapeutic community. Table, references