Community pharmacists are in a position to assume increased responsibility for preventing and resolving drug-related problems in ambulatory patients. Such an expanded role is mandated under provisions of the Omnibus Budget Reconciliation Act of 1990. The need for pharmacist oversight of drug therapy may be most acute in elderly patients. This study reports on a program to teach community pharmacists a process of assessing drug therapy of elderly patients and intervening to correct problems. Community pharmacists (N = 102) were assigned to treatment and control conditions. Both groups targeted patients meeting criteria and enrolled them into the study. Treatment group pharmacists, who participated in a training program, also assessed the medication use of enrolled patients to identify and resolve medication-related problems. Patients (N = 762) were telephoned by researchers 1 month after enrollment for an interview. Comparisons between treatment and control group patients were made on reports of pharmacist activities, knowledge of regimens, compliance, and potential drug therapy problems, such as interactions and side effects. Treatment patients were more likely to report that pharmacists provided information and assessed for problems than were control patients. These differences were maintained on 3-month follow-up questionnaires. No differences were found on the odds that patients indicated misunderstanding of regimens, non-compliance, or potential therapeutic problems.