The study was performed in order to ascertain the sustained smoking cessation rate in hospital patients who received a structured programme of advice and support from a counsellor and to estimate the cost-effectiveness of such an intervention. Hospital in-patients out-patients were referred by their physician/surgeon to the smoking cessation counsellor who provided advice to reinforce that of the doctor and gave support by repeated follow-up sessions, weekly in the first month and thereafter at three, six and twelve months. Of 1,155 patients referred to the counsellor, 114 (13%) failed to keep the first appointment and 348 (30%) attended for advice on one occasion only. Among the latter, the self-reported sustained cessation rate at one year was 5%. In the 663 patients who participated in the programme the validated (expired air CO) 12-month, sustained cessation rate was 21%. Allowing 7.5% success rate among patients receiving a physician's advice only, the cost of each additional success achieved as a result of the programme is 851 Pounds and the cost per life year saved is between 340 Pounds and 426 Pounds. Assuming that after one year's abstinence relapse rates are relatively small, this represents a sound investment in the light of the cost of treating patients with smoking-related illnesses and compares favourably with other smoking cessation strategies and health care interventions.