Developments in modern chemotherapy and radiotherapy mean that most patients with Hodgkin's lymphoma can now be cured. However, the long-term effects of anticancer treatment include an increased risk of a second malignant disease. We have done a systematic review of studies reporting long-term complications of the treatment of Hodgkin's lymphoma published in English since 1985. These studies show that risk of lung cancer is significantly increased in patients treated for Hodgkin's lymphoma, with a reported mean relative risk of 2.6-7.0 and a significantly increased absolute excess risk. The absolute excess risk increases with time from treatment, for as long as 20-25 years, and is highest in patients treated at age 45 years or older. Both chemotherapy and radiotherapy contribute to the risk, and evidence suggests that the effects are additive. Cigarette smoking seems to multiply the risk associated with both chemotherapy and radiotherapy. In the high-risk group of patients, 50-150 patients per 1000 are expected to develop lung cancer by 10-20 years after treatment. The role of screening in this group of patients has not yet been assessed, but an international study combining CT with genomic and proteomic assessment is planned.