Pediatric patients who have undergone cardiac surgery are at risk for renal insufficiency. The impact of pharmacist consultation in the pediatric cardiac intensive care unit (ICU) has yet to be defined. Patients admitted to the pediatric cardiac ICU at our institution from January through March of 2006 were included. Patient information, collected retrospectively, included: demographics, cardiac lesion/surgery, height, weight, need for peritoneal or hemodialysis, need for mechanical support, highest and lowest serum creatinine, ICU length of stay (LOS), renally eliminated medications, pharmacist recommendations (accepted or not), and appropriateness of dosing changes.There were 140 total admissions (131 patients; age: 3.0 +/- 6.3 years) during the study period. In total, 14 classes of renally eliminated medications were administered, with 32.6 +/- 56.4 doses administered per patient admission. Thirty-seven patient admissions had one or more medications adjusted for renal insufficiency; the most commonly adjusted medication was ranitidine. Patients who required medication adjustment for renal dysfunction were significantly younger compared to those patients not requiring medication adjustment. Pharmacist recommendations were responsible for 96% of medication adjustments for renal dysfunction, and the recommendations were accepted and appropriate all of the time. The monetary impact of pharmacist interventions, in doses saved, was approximately $12,000. Pharmacist consultation can result in improved dosing of medications and cost savings. The youngest patients are most at risk for inappropriate dosing.