Objective: To examine the effectiveness of routine clinic review in detecting relapse after treatment for Hodgkin's disease. Design: Review of hospital records. Setting: Regional centre for cancer treatment and research. Subjects: 210 patients with Hodgkin's disease recruited to a chemotherapy trial protocol between 1984 and the end of 1990 who had achieved a complete or partial remission after treatment. Main outcome measures: The number of clinic visits made by patients over the period of observation, the number of relapses occurring during that time, and the route by which relapse was detected. Results: The 210 patients generated 2512 outpatient reviews, and 37 relapses were detected. Thirty relapses (81%) were diagnosed in patients who described symptoms, which in 15 cases had resulted in an earlier appointment being arranged. In only four cases (11%; 95% confidence interval 4% to 25%) was relapse detected as a result of routine physical examination or investigation of a patient who did not have symptoms. Conclusions: Relapse of Hodgkin's disease after treatment is usually detected as a result of the investigation of symptoms rather than by routine screening of asymptomatic patients. It is therefore proposed that the frequency of routine follow up visits should be reduced and greater emphasis placed on patient education. This should underline the importance of symptoms and encourage patients to arrange an earlier appointment if these develop. Follow up after treatment for Hodgkin's disease has several functions but detection of relapse is probably the most important In Hodgkin's disease the relapse rate is maximal 12-18 months after the start of treatment but declines rapidly thereafter Relapse is usually identified as a result of the investigation of symptoms rather than by routine screening of asymptomatic patients Routine clinic visits should be reduced in frequency and far greater emphasis placed on patient education; this should underline the importance of symptoms and encourage patients to arrange earlier appointments if these develop