Colorectal cancer (CRC) is the third leading cause of cancer mortality among women. Screening can prevent the development of CRC or diagnose early disease when it can effectively be cured, however existing screening methods are underutilized. In this study, we examined the utility of an updated Health Belief Model to explain CRC screening adherence. The present study included 280 older women seeking routine mammography at a large, urban breast diagnostic facility. Overall, 50% of women were adherent to CRC screening guidelines. Multiple regression indicated that self-efficacy, physician recommendation, perceived benefits of and perceived barriers to screening accounted for 40% of variance in CRC screening adherence. However, there was no evidence for two mediational models with perceived benefits and perceived barriers as the primary mechanisms driving adherence to CRC screening. These findings may inform both future theoretical investigations as well as clinical interventions designed to increase CRC screening behavior.