Non-Hodgkin's lymphoma has been studied in the Pediatric Branch for at least 20 years, during which time a number of different treatment protocols have been used. Approximately 110 patients have apparently been cured of their lymphoma. The present protocol has no therapeutic component, but is designed to document the late effects that may have been encountered by our patients, either as a consequence of the disease or its treatment. In essence, patients who consent to participate will be asked a series of questions pertaining to the quality of their life and possible medical problems that they may be encountering. In addition, they will receive a complete physical examination and undergo non-invasive investigations designed to identify the presence of unsuspected late effects. Investigators in the Eye Clinic, Dental Clinic, Audiology, Cardiology and Endocrinology departments will participate in the protocol. As a part of the study, blood samples will be obtained to investigate the possibility that predisposing genetic factors may be identifiable in the patients normal cells (e.g., p53 mutations, evidence of DNA instability). If such abnormalities are detected, blood samples from family members will also be examined to determine whether the defect was inherited.