This paper provides a review and synthesis of research literature on the effects of shift work on workers’ physical health, mental health/well-being, and family life. The focus is on current knowledge, unanswered questions, and new directions for future research. The selection of research literature is guided by a general conceptual framework that identifies predictor variables, moderating variables, and outcome variables. The paper concludes with a discussion of the variables that should be incorporated into an agenda for future research.