This paper discusses the debate over the relative merits of scientific and precautionary approaches to the management of technological risk.The paper highlights the following points:rather than seeing ‘precaution’ as being in tension with ‘science based regulation’, the key elements of a precautionary approach are entirely consistent with sound scientific practice in responding to intractable problems in risk assessment such as ‘ignorance’ and ‘incommensurability’there can be no simple analytical, instrumental or institutional ‘fixes’ for the complexities encountered in the management of technological riskspolicy making must be based on the available scientific information, but science on its own is not enoughthere is a need for flexibility and learning in regulation itselfthere are a variety of very practical and robust methods which are entirely consistent with the established procedures of risk assessment and which can be applied under a broader and more pluralistic precautionary approach, taking account of a variety of contending options and their associated benefits as well as their risks.[adapted from author]