The number of long-term cancer survivors (≥5 years after diagnosis) in the U.S. continues to rise, with more than 10 million Americans now living with a history of cancer. Along with such growth has come increasing attention to the continued health problems and needs of this population. Many cancer survivors return to normal functioning after the completion of treatment and are able to live relatively symptom-free lives. However, cancer and its treatment can also result in a wide range of physical and psychological problems that do not recede with time. Some of these problems emerge during or after cancer treatment and persist in a chronic, long-term manner. Other problems may not appear until months or even years later. Regardless of when they present, long-term and late effects of cancer can have a negative effect on cancer survivors' quality of life. This article describes the physical and psychological long-term and late effects among adult survivors of pediatric and adult cancers. The focus is on the prevalence and correlates of long-term and late effects as well as the associated deficits in physical and emotional functioning. In addition, the emergence of public health initiatives and large-scale research activities that address the issues of long-term cancer survivorship are discussed. Although additional research is needed to fully understand and document the long-term and late effects of cancer, important lessons can be learned from existing knowledge. Increased awareness of these issues is a key component in the development of follow-up care plans that may allow for adequate surveillance, prevention, and the management of long-term and late effects of cancer. Cancer 2008. © 2008 American Cancer Society.