Medication reconciliation at hospital admission has reduced medication errors, but less is known about the pediatric population, particularly which patients may benefit most from reconciliation. This retrospective study of pediatric patients who experienced at least one medication reconciliation error found children older than 5 years, taking 4 or more medications, or with neurological or onco-hematological conditions were at increased risk of errors. Prioritization of these populations may improve the effectiveness of medication reconciliation.