Human implant technologies are subject to continual innovation and proliferation, raising important issues for technology testing, healthcare sciences, clinical performance and risk assessment, and regulation. The regulatory environment of medical devices is being shaped by harmonisation of standards in the European Union. The aim of this paper is to compare the histories and current regulatory environment of two technologies, breast implants and artificial hips, and to consider the implications of this comparison for a sociological healthcare research agenda to investigate the issues raised. The main focus is upon developments in the United Kingdom. Major points of contrast between the two technologies include the institutional contexts in which clinical evidence has been marshalled for government attention; the relative importance of strategic alliances between clinicians and manufacturers in the innovation process; the degree of public controversy evident; the varying definitions of an 'adverse incident' within medical device vigilance systems; and in the UK the presence of a national register for breast implants but not for hip implants. Inter-national contrasts in these dimensions are noted. The analysis suggests that improved understanding is required of the institutional, organisational and professional processes involved in implant technology innovation and regulation. A comparative research agenda is proposed, focusing upon: innovativeness and proliferation; safety and technological standards; clinical and social outcomes; and consumer/user information and choice. It is concluded that research in these areas will enhance the 'evidence-base' for the evaluation of human implant technologies in the context of their innovatory and regulatory environments.