Previous clinical research on hallucinogen-assisted psychotherapy reported efficacy in treating substance abuse disorders, similar to what has been reported in naturalistic studies of peyote use among Native American Church members. Urban use of the Amazonian hallucinogenic brew, ayahuasca, is increasingly common in syncretic Brazilian ayahuasca religions, and anecdotal reports suggest recovery from substance dependence among those who participate in their rituals. We sought to assess more quantitatively the effects of Brazilian ayahuasca-using church membership on substance dependence. We employed a modified questionnaire using DSM-IV criteria to determine the presence of substance dependence within a sample of members of a branch of the Santo Daime Brazilian ayahuasca religion. Nearly half of these church members reported substance dependence before joining the religious organization; of these, 90 % reported cessation of use of at least one substance upon which, before church membership, they reported dependency. While these preliminary data require confirmation using more rigorous criteria, they suggest a potential role for ayahuasca, within a particular context, in the treatment of substance dependence