Before participants can be enrolled in a clinical trial, an institutional review board (IRB) must determine that the risks that the research poses to participants are ‘reasonable.’ This paper examines the two dominant frameworks for assessing research risks and argues that each approach suffers from significant shortcomings. It then considers what issues must be addressed in order to construct a framework for risk assessment that (a) is grounded in a compelling normative foundation and (b) might provide more operationally precise guidance to the deliberations of various stakeholders. The paper concludes by sketching the outlines of what is referred to as the ‘Integrative Approach’ to risk assessment and by highlighting some of the ways in which this approach may be more promising than current alternatives. Copyright © 2006 John Wiley & Sons, Ltd.