Handoff improvement is a national patient safety priority. The Accreditation Council for Graduate Medical Education now requires residency programs to provide formal handoff education to trainees. This study evaluated the implementation of an inpatient handoff bundle for pediatric resident physicians. The multifaceted intervention included team training, standardized communication, electronic documentation, and new team handoff structures. In the uncontrolled, before-and-after analyses, medical errors and preventable adverse events decreased substantially. The intervention did not adversely affect resident workflow. Residents were found to spend more time in direct contact with patients in the post-intervention period. A related editorial notes that this study presents promising evidence that improving handoffs can reduce patient harm.