Administration of medication in an environment such as operating rooms is extremely complex and considerably increases the possibility of errors . This study was performed to analyze how medication is stored, prescribed and administered in operating rooms. Eight operating rooms in a Northern Italy hospital were taken into consideration, analyszing the medication prescribed in 96 working days. The critical points that emerged from the study regarded tasks performed by nurses , but also other professionals. This pilot study was useful for acquiring basic data on the working processes that surround the administration of medication.