Renal transplantation is an established treatment for end-stage renal disease. Most renal transplant patients take multiple medications for a long period of time to maintain immunosuppression as well as to treat concomitant chronic diseases. Since some medications prescribed for these patients have narrow therapeutic ranges, optimal pharmacotherapy is vital. However, pharmacists can qualify the role in assisting patients and physicians to solve and reduce drug-related problems. The purpose of this trial was to investigate the effects on treatment outcomes by clinical pharmacists joining renal transplant clinics to provide pharmaceutical care. We enrolled 37 renal transplant patients who visited the renal transplant clinic in our medical center from May 2005 through August 2006. The responsibility of the clinical pharmacist was to interview patients, review medication regimens, and make therapeutic recommendations for 3 hours every Tuesday morning. According to potential clinical impacts, pharmacist recommendations were divided into 6 scales, evaluating physician acceptance of pharmacist recommendations and impact on treatment outcomes. Fifty-five pharmacotherapy recommendations were made for the 37 renal transplant patients during the trial period, of which 81.8% were classified as clinically significant. The drug classes most commonly involved were cardiovascular medications, immunosuppressants, and antimetabolites (32.6%, 23.9%, and 26.1%, respectively). Physician acceptance rates of recommendation types and drug classes were 96.0% and 97.1%, respectively. Among the cases in which the recommendations were accepted, 94.2% of patients showed improved conditions. We concluded that clinical pharmacists joined to renal transplant clinics provide pharmaceutical care with a positive potential impact on physician prescriptions and patient outcomes.