Abstract Objective: Describe outcomes of a religiously-tailored peer-led group educational intervention addressing mammography-related barrier beliefs of American Muslims. Methods: We used focus groups and interviews with a diverse group of Muslim women aged 40 and older to identify salient behavioral, normative and control beliefs regarding mammography. We used these data to design the curriculum and messaging for a mosque-based intervention involving peer-led group education. A novel model for religious tailoring was developed to address barrier beliefs by reframing, reprioritizing, and/or reforming belief structures. Peer educators were recruited/trained from mosques to match the ethnic composition of target population. The classes involved facilitated discussions and guest-led didactics covering religion and health, and mammography guidelines. Survey data was collected pre-, post, 6 months, and one-year post-intervention which captured changes in three primary outcome variables (1) perceived mammography intention, likelihood, confidence, (2) breast cancer knowledge and (3) receipt of mammograms. Resonance with barrier and facilitator beliefs was also measured. Results: Fifty-eight Muslim women who had not had a mammogram in the past two years participated. Mean age was 50 years, with 29 being South Asian and 18 being of Arab descent. With respect to changed intention/likelihood/confidence pre-post there was a significant increase in mean perception of likelihood to obtain a mammogram (0.29, P = 0.01). Mammography knowledge also significantly increased following the intervention (p = 0.0002). Importantly, 22 participants received a mammogram at one-year follow-up. With respect to belief structures, a marginally significant increase was observed in level of agreement with mammography facilitator beliefs (p = 0.08) post-intervention. Although overall level of agreement with the outcome variable of mammography barrier beliefs did not change following the intervention (p = 0.94), there was a significant decrease in agreement with the specific belief in fatalism (p = 0.03). Multivariable models demonstrated that higher levels of agreement with fatalistic beliefs at baseline was significantly associated with a lower odds of increased mammography knowledge following the intervention (OR = 0.73), while higher religiosity at baseline was significantly associated with higher odds of increased mammography knowledge following the intervention (OR = 1.90). Conclusion: Our mosque-based intervention involving religiously-tailored messages and peer-led classes demonstrated efficacy in behavioral change by improving Muslim women's self-reported likelihood of obtaining mammograms and having 38% of participants obtained a mammogram within a year. Citation Format: Aasim I. Padela, Sana Malik, Shaheen Nageeb, Stephen Hall, Fatema Mirza, Monica Peek, Michael Quinn. Outcomes from a religiously tailored intervention to enhance mammography uptake among American Muslims [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5273.