The purpose of this retrospective cohort study was to evaluate the effect of smoking habits and patient compliance on the outcomes of supportive periodontal therapy (SPT) (tooth loss and residual pockets defined by probing depth of >= 5 mm) in a private practice situation. Eighty-seven patients, who completed active periodontal treatment and then followed an SPT program for at least 5 years, were recruited from the patient pool of a private dental practice. After active periodontal therapy and at the follow-up examination 5 - 11 years later, pocket probing depths (PPD) and tooth loss were assessed, and the patients were divided into 4 subgroups based on their smoking history: non-smokers (NS); occasional smokers (OS); moderate smokers (S); and heavy smokers (HS). The patient cohort was also divided into 4 subgroups based on patient compliance (mean delay from the scheduled recall sessions): fully compliant ( 1 week); compliant within 1 - 3 weeks; compliant within 3-6 weeks; and not compliant (> 6 weeks). The mean tooth loss per patient and year ranged from 0.11 - 0.18 in the various subgroups with no significant differences between them. After a mean observation period of 7.3 ± 1.5 years, the incidence of new sites with residual probing depth of >= 5 mm varied between 1.2% for the NS and 13.8% for the HS (p 0.05,), and between 3.2% for the compliant and 5.8% for the non-compliant patients. Smoking habits significantly influenced the treatment outcomes of SPT, while compliance was less influential regarding the incidence of new residual pockets during 7.3 years of SPT. Keywords: supportive periodontal therapy, SPT, compliance, smoking habits, tobacco, smoking, periodontal pockets, reinfection, maintenance, tooth loss