Many cancer patients continue to smoke past diagnosis and treatment, even though smoking in some cases may cause more side effects and increase the risk of treatment failure. We developed and evaluated a nurse-led smoking cessation programme on 50 patients with head and neck (H&N) cancer undergoing radiotherapy (RT) with 1-year follow-up. To evaluate the effectiveness of the programme (proportion of smoke-free patients), smoking status was tested by measuring carbon monoxide in expired air. Thirty-seven patients (74%) were tested smoke-free weekly during the RT period. At the 1-year follow-up visit, 28 patients (68%) were tested smoke-free. The results indicated that even H&N cancer patients with a heavy smoking history and multiple abuses could quit smoking with systematic support but a more sophisticated evaluation including larger study populations and control groups are needed.