Past research indicates that social support is beneficial to cancer patients in adjusting to the stress of the disease. In this article, a brief review of research on social support is provided as a framework within which support among cancer patients can be examined. Research on cancer is then reviewed, and selected results from an investigation of 79 cancer patients are reported. The findings indicate that: health care providers are particularly important sources of support to cancer patients; of several types, emotional support is seen as especially helpful; and the types of support seen as most helpful by those with cancer depends on who provides them. In addition, variability in stress among cancer patients mediated the frequency of interpersonal problems, and the association between support and various indices of adjustment. Implications of these results for future research on social support in stressed populations, especially cancer patients, are discussed.