Objectives: The aims of this study were to determine the relationship between compliance in patients with chronic periodontitis and the efficacy of nonsurgical periodontal treatment as well as to investigate the factors that influence the compliance of patients with chronic periodontitis. These aims may be useful for determining the prognosis and improving the efficacy of treatment. Method and Materials: Four hundred patients with chronic periodontitis were classified into three groups: the complete compliance group (S1), the erratic compliance group (S2), and the failing compliance group (S3). The patients who were in group S1 received supportive periodontal therapy (SPT) on time: they presented for their appointments within 2 months of the scheduled date; the patients who missed their appointments by more than 2 months or who completely missed a return visit one or more times, were placed in group S2; and the patients who never returned to receive SPT were assigned to group S3. They completed a questionnaire about compliance and underwent a clinical periodontal examination. SPSS 13.0 was used for the statistical analysis. Results: Groups S2 (49.4%) and S3 (34.1%) were significantly different from group S1 (87.0%) (P .05) in their understanding that periodontal disease is always associated with other diseases. The analysis of severe pain during the treatment revealed significant differences (P .05) between group S1 (22.2%) and group S3 (39.9%). Awareness of chronic periodontitis and comfort during treatment are important factors influencing patient compliance. The distance of the patient's residence from the hospital, working hours, and attitudes of family members also affect patient compliance. Conclusion: Doctors should educate patients about oral health and manage their patients' comfort as much as possible during treatment, thereby enhancing patient compliance and achieving better treatment efficacy. Keywords: chronic periodontitis, compliance, factor analysis, supportive periodontal therapy