Abstract: Background. The Diabetes Check is a brief structured interaction that was designed to facilitate patient-pharmacist conversations about monitoring A1c, blood pressure, and cholesterol numbers (diabetes ABCs) during routine prescription counseling. Research questions. Did students who performed Diabetes Checks improve more in attitudes and behavior than students who performed a control activity? Secondary research questions evaluated predictors of predictors of students': (1) intentions to ask about diabetes ABCs in the future, (2) behavior in asking about the diabetes ABCs, and (3) routine behavior. Methods. A randomized controlled trial was conducted in clerkship pharmacies in Wisconsin. In the intervention group, pharmacy students used the Diabetes Check with 5 to 10 patients with diabetes. In the control group, pharmacy students were asked to review profiles of two patients with diabetes. Students were asked to complete a pre- and post-clerkship survey which assessed students' self-efficacy, outcome expectancies, role beliefs, mattering, intentions to ask about diabetes ABCs, frequency of monitoring diabetes ABCs, and experiences with the Diabetes Check. Results. Of 130 student, 119 (92%) completed surveys at both time points. Students who completed the Diabetes Check intervention had greater improvements in the frequency of monitoring patients' A1c values and in their Counseling Role Orientation and Negative Outcome Expectancies than students in the control group. Students' intentions to monitor diabetes were predicted by pharmacy site counseling, monitoring role beliefs (MRO), self-efficacy, and positive outcome expectancies. Mattering was a predictor of intentions in the control group. Students' frequency of asking about blood pressure and cholesterol were predicted by pharmacy site counseling, self-efficacy and MRO. Students frequency of asking about A1c was predicted by pharmacy site counseling, self-efficacy, MRO, and completing the Diabetes Check assignment. Routine behavior did not have any significant predictors. Conclusions. The Diabetes Check improved pharmacy students' monitoring behavior, general counseling beliefs, and negative outcome expectancies. Monitoring intentions and behaviors were influenced by pharmacy site counseling, monitoring role beliefs, and self-efficacy. The Diabetes Check is a practical intervention to get patients and community pharmacists working together to monitor diabetes and potentially improve patient health.