Background: Pharmacists in various settings have been effective in initiating diabetes treatment. Patients with diabetes require ongoing disease management, and community pharmacists are in a strategic position to provide such extended care. Little is known, however, about the effects of community pharmacist–provided interventions beyond the initial treatment period. Objective: To evaluate the effect of community pharmacist–provided extended diabetes care service on primary clinical outcomes, including hemoglobin A _1c (A1C), low-density lipoprotein cholesterol (LDL-C), and blood pressure, and on patients' reported self-care activities. Methods: A randomized controlled trial was conducted in patients with diabetes. Participants had already completed at least 2 diabetes education sessions at a local diabetes education center. Nine specially trained pharmacists administered interventions during up to 4 quarterly visits per patient. Interventions included discussing medications, clinical goals, and self-care activities with patients and recommending medication changes to physicians when appropriate. The main outcome measures were 12-month changes in A1C, LDL-C, blood pressure, and self-report of self-care activities. Results: Seventy-eight patients participated in the study (36 intervention, 42 control); 66 were included in the final analysis (31 intervention, 35 control). Compared with changes in the control group, patients who received interventions significantly increased the number of days per week that they engaged in a set of diet and diabetes self-care activities (1.25 and 0.73 more days/wk, respectively). The mean 12-month changes for A1C, LDL-C, and blood pressure were not significantly different between the 2 study groups. Conclusions: Although pharmacist-provided interventions did not demonstrate statistically significant improvements in clinical outcomes over the study period, study results did show that pharmacists were effective at increasing the number of days that patients spent engaging in healthy diet and diabetes self-care activities. Addressing lifestyle and self-care behaviors can be a beneficial component of a pharmacist-provided extended diabetes care service.