The importance of learning from medical error has recently received increasing emphasis. This paper focuses on prescribing errors and argues that, while learning from prescribing errors is a laudable goal, there are currently barriers that can prevent this occurring. Learning from errors can take place on an individual level, at a team level, and across an organisation. Barriers to learning from prescribing errors include the non-discovery of many prescribing errors, lack of feedback to the prescriber when errors are discovered by other healthcare professionals, and a culture that does not encourage reflection on errors together with why they occurred and how they can be prevented. Changes are needed in both systems and culture to provide an environment in which lessons can be learnt from errors and put into practice.