Our aim was to assess the efficacy after 6 months of combined smoking cessation therapy using nicotine substitution with both chewing gum and patches. Sixty-six (25 women, 41 men) heavy smokers (38.04 packs/year and 8.42 mean score on Fagerström test) were followed between September 1995 and March 1997. Most patients were referred by respiratory, cardiology or ear-nose-and-throat outpatient clinics. The patients were prescribed 24-hour nicotine substitution therapy with 21 mg patches, plus chewing gum providing 2 mg of nicotine (3 to 10 per day) for a minimum of 8 weeks and a maximum of 12, with gradually decreasing doses. The patients were checked 1, 2, 4, 8, 12 and 24 weeks after enrollment. Expired air carbon monoxide was measured to confirm abstinence at each checkup and a simple questionnaire was filled in to assess abstinence syndrome and detect the presence of treatment side effects. Rate of abstinence achieved with this protocol after six months of follow-up was 37.9%. The failure rate was highest in the first week (33%) but gradually decreased until week 12. No patients had to abandon treatment due to side effects.