Background. The post-treatment follow-up is well-integrated in the oncologic care tradition, based on the risk of developing recurrent disease or new primary tumors in treated patients. Furthermore, follow-up serves as an opportunity to monitor treatment effects and to provide clinical care of side effects. In this study we measured the activity and effectiveness of routine follow-up in head and neck cancer and assessed the value of follow-up from the perspectives of both physicians and the patients. Patients and methods. During a period of six weeks a prospective national cross section cohort of 619 patients attending regular follow-up were enrolled. All patients had received intended curative treatment for head and neck cancer and all were followed according to DAHANCA guidelines. Data were collected by the physician filling in a registration form containing chosen key parameters and patients filling in a validated questionnaire. Results. The majority (91%) of the 619 visits was planned, and 75% of all visits included either tumor or treatment-related problems. Suspicion of recurrent disease led to further diagnostic work-up in 80 visits (13%). A total of 29 recurrences were found, and of these seven (25%) were asymptomatic, i.e. The "number needed to see" to detect one asymptomatic recurrence was 99. Treatment-related normal-tissue problems were addressed in 72% of all visits, and among these 18% required intervention. Although the majority of problems (either suspicion of recurrent disease or late effects) occurred within a few years after treatment, 39% of patients seen after three years also had problems. The majority of patients (97%) expressed satisfaction with the planned follow-up. Conclusion. Only few relapses are found in asymptomatic patients at routine follow-up, with one silent recurrence detected per 99 visits. However, head and neck cancer survivors have a substantial need for management of sequelae. In this context, a centralized routine follow-up may still be worthwhile.