The last four decades have seen tremendous improvements in the survival of children diagnosed with cancer, with 5-year survival rates now at 80%. The burgeoning population of childhood cancer survivors creates an obligation to understand the health and well-being of these individuals. The use of cancer therapy at an early age can produce complications that may not become apparent until years later; it has been demonstrated quite conclusively that approximately two thirds of these survivors will experience at least one late effect and about one third will experience a late effect that is severe or life threatening. Long-term complications in childhood cancer survivors, such as impairment in growth and development, neurocognitive dysfunction, cardiopulmonary compromise, endocrine dysfunction, renal impairment, gastrointestinal dysfunction, musculoskeletal sequelae, and subsequent malignancies, are not only related to the specific therapy employed, but may also be determined by individual host characteristics. This review describes some of the known late effects described in childhood cancer survivors in order to suggest reasonable starting points for evaluation of specific long-term problems in this unique and growing population.