© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ. Objectives Paediatric cardiopulmonary arrest resuscitation is a critically important skill but infrequently used in clinical practice. Therefore, resuscitation knowledge relies heavily on formal training which is vulnerable to rapid knowledge decay. We evaluate knowledge and skill retention post-training using rapid cycle deliberate practice (RCDP). Design Pilot, non-blinded, single-arm study. Setting Pediatric Simulation Center at Children's of Alabama. Participants 42 paediatric residents at a large, tertiary care, academic children's hospital were enrolled in this simulation-based resuscitation study. Interventions Each participant led a 7 min preintervention arrest scenario as a baseline test. After testing, participants were trained individually in the paediatric advanced life support (PALS) skills necessary for resuscitation of a patient in pulseless electrical activity and ventricular fibrillation using RCDP - a simulation method using frequent expert feedback and repeated opportunities for the learner to incorporate new learning. Immediately post-training, participants were retested as leaders of a different paediatric arrest scenario. 3 months post-training participants returned to complete a final simulation scenario. Main outcome measures To evaluate knowledge and skill retention following PALS training. Results Preintervention data demonstrated poor baseline resident performance with an average PALS score of 52%. Performance improved to 94% immediately post-training and this improvement largely persisted at 3 months, with an average performance of 81%. In addition to improvements in performance, individual skills improved including communication, recognition of rhythms, early chest compressions and rapid administration of epinephrine or defibrillation. Conclusions RCDP training was associated with significant improvements in resident performance during simulated paediatric resuscitation and high retention of those improvements.