The aim of the present study was to analyze specifically the influence of the 30 facets of personality assessed by the NEO-PI-R on the short and long-term outcomes of a smoking cessation treatment program. The results at the end of treatment and in the 12 months follow-up indicated the influence of facets of personality and confirmed that previous level of consumption and the degree of dependence of the smokers are key elements for explaining treatment outcome, according to previous studies.