Denying individual liberty on the basis of community protection requires a defensible mechanism for identifying those sex offenders likely to reoffend. Reliance on expert opinion has become routine, even when such opinions have limited accuracy. Careful attention to the empirical literature, however, has the potential to improve risk assessments for sexual offenders. This article describes different approaches to risk assessment, summarizes the empirical literature on individual risk factors, and reviews recent attempts to create actuarial risk scales for sex offense recidivism. A number of historical and highly stable predictor variables have been documented (e.g., offense history and deviant sexual preferences), but the research on dynamic (changeable) risk factors has been limited. Consequently, the research is more useful for identifying high-risk offenders than for determining when they could be safely released into the community.