Objective: To evaluate the effectiveness of a physician-led rapid response team (RRT) program on morbidity and mortality following unplanned admission to the pediatric intensive care unit (PICU). Design: Before-after study. Setting: Single center quaternary referral PICU. Patients: All unplanned PICU admissions from the ward from 2005-2011. Interventions: The dataset was divided into pre- and post-RRT groups for comparison. Measurements and Main Results: A Cox proportional hazards model was used to identify the patient characteristics associated with mortality following unplanned PICU admission. Following RRT implementation, PRISM-III illness severity was reduced 28.1%, PICU length of stay (LOS) was less 19.8%, and mortality declined 22%. Relative risk of death following unplanned admission to the PICU after RRT implementation was 0.685. Conclusions: For children requiring unplanned admission to the PICU, RRT implementation is associated with reduced mortality, admission severity of illness and length of stay. RRT implementation led to more proximal capture and aggressive intervention in the trajectory of a decompensating pediatric ward patient.