Substantial improvements in the past few decades in cancer detection and supportive care along with advances in therapy have led to growing numbers of cancer survivors. In view of the prolongation of survival in increasing numbers of patients, identification and quantification of the late effects of cancer and its therapy have become critical. One of the most serious events experienced by cancer survivors is the diagnosis of a new cancer. The number of patients who have second or higher-order cancers is increasing, and solid tumors are a leading cause of mortality among several populations of long-term survivors, including patients who have Hodgkin lymphoma. The focus of this article is treatment-associated malignancies in survivors of selected adult cancers.