The extent to which the medical device manufacturers are responsible for actively monitoring the performance of their products after they have successfully passed the rigorous pre-market approval process has always been a matter of diverse opinion. Within Europe, the law is unhelpfully vague on this point. While there are some comparatively clear obligations for reporting incidents to the authorities (known as the 'vigilance system'), little detail is given on how diligently the manufacturer should try to find out about such incidents. In the early stages of the European Community Directives covering medical devices, there was much emphasis upon formulating guidance to help interpret the vigilance reporting requirements. It is, however, only recently that attention has turned to attempting to clarify what is expected from post-marketing surveillance (PMS) in its broader sense. This article discuses both the vigilance and PMS processes and outlines the currently available European, and particularly UK, guidance documents which are aimed at promoting a more level playing field across industry where these activities are concerned. In particular, it explains the principle differences between vigilance and post-marketing surveillance: the former being the reporting of adverse incidents by manufacturers to the regulatory authorities and their subsequent sharing of key incident data between each other; the latter being the process by which information on overall devise performance is captured, analysed and acted upon. Nevertheless, it is still a struggle to gain widespread appreciation that these two activities are not in fact one and the same.