This review focuses on why people decide to obtain or to avoid screening for cancer. We discuss three topics: (a) physician prompts that may elicit compliant screening behavior, (b) the independent and joint effects of risk perceptions and worry, and (c) the costs and benefits of getting screened. Overall, the data suggest that each of these factors will influence screening. So, for example, people are more likely to seek screening if a physician recommends the behavior, if they feel personally vulnerable and worry a little about cancer, if insurance covers the screening, and if they believe that the test is an effective early detection procedure. Future research needs include studies comparing theories, longitudinal rather than cross-sectional studies, and true experiments. We also need to know more about why physicians are such powerful change agents and the trade-offs of increasing personal risk versus exacerbating worry. Practical recommendations for promoting cancer screening include encouraging physician interventions, explaining risk, and lowering the costs while emphasizing the benefits of screening.