This study tested the effects of two theory-based interventions to increase fruit and vegetable intake.Hypothesized intervention mediators included self-efficacy (SE), social support (SS), autonomous motivation (AM), and controlled motivation (CM).At baseline, 1,021 African American adults were recruited from 16 churches randomized to one comparison and two intervention groups: Group 1 (standard educational materials), Group 2 (culturally targeted materials), and Group 3 (culturally targeted materials and telephone-based motivational interviewing).A well-fitted model based on structural equation modeling-χ2(df=541, N=353,325)=864.28, p<.001, normed fit index=.96,nonnormed fit index=.98, comparative fit index =.98,root mean square error of approximation=.042-demonstrated that AM was both a significant mediator and moderator.In the subgroup with low baseline AM, AM mediated 17% of the effect of the Group 3 intervention on fruit and vegetable intake.Conversely, SS, SE, and CM were not significant mediators.Implications related to theory and intervention development are discussed. © 2011 by SOPHE.