The Italian League against Cancer organizes a group behaviour therapy program for smoking cessation in Milan and Rome. Groups meet for 8-9 sessions; sessions are managed by a therapist. In the analized courses participants are 43-44 years on the average, with a middle/high level of education. They are heavy smokers with a high level of nicotine dependence and they greatly trust in the program. At the end of the program 67% of participants in Milan and 76% in Rome declare they no longer smoke. One year later, phone interviews show that 22% of participants in Milan and 25% in Rome are still non smokers. At the end of the program quitting-smoking predictors are: attendance at at least 6-7 sessions, smoking less than 30 cigarettes a day before the course and male gender; one year later attendance at at least 6-7 sessions, and scarce nicotine dependence (smoking less than 30 cigarettes a day before the program or a low score at the Fagerström Tolerance Questionnaire).