Medication errors are a common and significant causes of patient harm. This retrospective study examined regional prescription registry (RPR) data at a single Italian hospital at 4 comparison points, pre-admission, admission, hospitalization, and post-discharge. Researchers identified 4,363 discrepancies among 14,573 prescriptions originating from 298 patients with a mean age of 71.2 years. Approximately one third of the discrepancies (1,310) were classified as unintentional and the majority (62.1%) of those were found when comparing the prescriptions during the transition from  hospital discharge and the 9-month follow up. The study points to the need for enhanced communication between hospitalists and primary care providers at the hospital-home interface.