This paper reviews findings regarding the influence of cancer worry on cancer screening behaviors. The role of cancer worry in motivating cancer screening has been pursued for over 30 years. Recent concerns that high levels of cancer worry may impede the screening behavior of high-risk individuals have further prioritized this area of research. Despite heavy attention in the literature, there is currently no theoretical or empirical consensus concerning whether cancer worry motivates or inhibits cancer screening behaviors. We focus the review on four questions: (1) What is cancer worry? (2) To what extent are people worried about cancer? (3) What are the predominant theoretical approaches to understanding the role of cancer worry in cancer screening behaviors? (4) What is the empirical evidence for the role of cancer worry in cancer screening behaviors? We identify factors that have hampered theoretical and empirical advancement, including divergent definitions and measurement strategies for cancer worry, low to moderate levels of cancer worry even among those at high risk, and a reliance on cross-sectional research designs. The review clarifies the current state of this literature, and proposes future research strategies, including an expanded emphasis on cancer worry and cancer screening among men and diverse racial/ethnic groups.