Paramedic training and skills have been introduced in the United Kingdom in an attempt to improve prehospital patient care. There is presently little control and quality assurance in this potentially difficult environment and paramedic protocols have not been validated. We studied the use of nalbuphine by paramedics for patients with major injury in West Yorkshire. A case-control study was carried out using two cohorts of patients from the regional Major Trauma Outcome Study (MTOS) database; one group had received prehospital nalbuphine by paramedics (the intervention) and a matched group who had not (the control). Both groups of patients were reviewed by a panel of three consultants and a paramedic to assess which patients received or could have received nalbuphine appropriately. Only 85 patients from a database of 4170 patients received nalbuphine. Fifty-two (61%) patients were thought by the panel to have been given nalbuphine appropriately. The panel also concluded that 21 (18%) of the 115 patient control group could have been administered nalbuphine but did not receive the drug. This study demonstrates inadequate and sometimes inappropriate use of nalbuphine in prehospital trauma care. Quality assurance and audit systems should be implemented to identify and correct these deficiencies.