We aimed to assess whether a triple-faceted intervention program administered in the primary care setting could decrease the risk of insufficient adherence to primary care physician (PCP) appointments among this patient population. We conducted a cluster-randomized controlled study to assess the effects of a 1-year intervention. The primary outcome was insufficient adherence to regular PCP attendance for diabetes treatment, defined as failure to visit a PCP within 2 months of an original appointment date. The intervention consisted of mailing patient reminders of their PCP appointments, providing patients with health education aimed at lifestyle modification and benchmarking PCP procedures. Eleven municipal level district medical associations employing 192 PCPs were divided into two subregions for assignment to intervention and control clusters, with 971 and 1,265 patients assigned to the intervention and control groups, respectively. Primary outcome data were available for 2,200 patients. The intervention reduced insufficient adherence to regular PCP appointments by 63% (hazard ratio, 0.37; 95% confidence interval [CI], 0.23-0.58). In conclusion, a triple-faceted intervention program consisting of health education, appointment reminders, and physician benchmarking may decrease the risk of incomplete adherence to regular PCP appointments by diabetes patients.