The use of pediatric ventricular assist devices (VADs) continues to evolve with the availability of smaller blood pumps. We examine the correlation of implanting appropriate sized blood pumps with a lower incidence of VAD related complications (VADRC). A 7-year retrospective review was undertaken for all pediatric VAD patients. Optimal VAD hemodynamics were defined as cardiac index of 2.7 L/m2 and rate of 80 beats per minute (bpm) with complete fill/empty of the blood pump. Patient/blood pump size match, VAD rate and fill/empty ratios were calculated (optimum = 1.0) and then correlated with incidence of VADRC. The study included 22 patients, mean age 9.77 years (6 mo-18 yrs) and mean body surface area (BSA) of 1.14 m2 (0.14 m2-2.32 m2), who underwent VAD implantation. VADRC included death while on support (n = 5), bleeding requiring reoperation (n = 8), hemolysis (n = 2), neurologic events (n = 2), thrombus formation (n = 3), and infection (n = 3). Six patients were bridged to transplant without any VADRC. This subset of patients had a mean blood pump size match ratio of 0.98, VAD rate ratio of 0.92 and fill/empty ratio of 1.00. Patients with VADRC (n = 16) were found to have a mean blood pump size match ratio of 0.72, VAD rate ratio of 0.72 and fill/empty ratio of 0.78. We report a series of pediatric patients with wide ranging BSA receiving VAD implantation. Selection of appropriate sized blood pumps can be correlated with decreased VADRC.