Post-authorisation safety studies (PASS), whether interventional or, more commonly, non-interventional (NI), can be used by entities such as the European Medicine Agency´s Pharmacovigilance and Risk Assess ment Committee to oblige drug companies to collect data on approved products. NI PASS study reports should be drafted according to a particular mandated format, which may not be intuitive for writers more familiar with clinical study reports for interventional trials. This article addresses the structure of NI-PASS reports, comparing and contrasting with the clinical study reports of interventional trials.