Health literacy is increasingly recognized as a critical factor affecting communication across the continuum of cancer care. We reviewed research on health literacy and examined its impact on cancer outcomes and communication. According to the National Adult Literacy Survey (NALS), considered the most accurate portrait of literacy in our society, about one in five American adults may lack the necessary literacy skills to function adequately in our society. As patients, such individuals are at a disadvantage in their capacity to obtain, process, and understand cancer information and services needed to make appropriate health care decisions. Patients with poor health literacy have a complex array of difficulties with written and oral communication that may limit their understanding of cancer screening and of symptoms of cancer, adversely affecting their stage at diagnosis. In addition, these barriers impair communication and discussion about risks and benefits of treatment options, and patient understanding of informed consent for routine procedures and clinical trials. More research is needed to identify successful methods for educating and communicating with patients who have limited health literacy. Based on our own experience, we offer practical communication aids that can help bridge the cancer communication gap.