BACKGROUND: Despite the well-known beneficial effects of statins, many patients do not adhere to chronic medication regimens. OBJECTIVE: To implement and assess the effectiveness of a community pharmacy based pharmaceutical care program developed to improve patients' adherence to statin therapy. METHODS: An open-label, prospective, randomized controlled trial was conducted at 26 community pharmacies in the Netherlands. New users of statins who were aged 18 years or older were randomly assigned to receive either usual care or a pharmacist intervention. The intervention consisted of 5 individual counseling sessions by a pharmacist during a 1-year period. During these sessions, patients received structured education about the importance of medication adherence, lipid levels were measured, and the association between adherence and lipid levels was discussed. Adherence to statin therapy was assessed as discontinuation rates 6 and 12 months after statin initiation, and as the medication possession ratio (MPR), and compared between the pharmaceutical care and usual care groups. RESULTS: A total of 899 subjects (439 in the pharmaceutical care group and 460 in the usual care group) were evaluable for effectiveness analysis. The pharmaceutical care program resulted in a significantly lower rate of discontinuation within 6 months after initiating therapy versus usual care (HR 0.66, 95% Cl 0.46 to 0.96). No significant difference between groups was found in discontinuation at 12 months (HR 0.84, 95% Cl 0.65 to 1.10). Median MPR was very high (>99%) in both groups and did not differ between groups. CONCLUSIONS: These results demonstrate the feasibility and effectiveness of a community pharmacy based pharmaceutical care program to improve medication adherence in new users of statins. Frequent counseling sessions (every 3 months) are necessary to maintain the positive effects on discontinuation. Although improvements are modest, the program can be applied easily to a larger population and have a large impact, as the interventions are relatively inexpensive and easy to, implement in clinical practice