The aim of this chapter is to focus on the maintenance phase (supportive periodontal treatment). This chapter covers the importance of maintenance phase, rationale for supportive periodontal therapy, causes for recurrence of periodontal disease, goals of supportive periodontal treatment, objectives of maintenance phase, parts of maintenance phase, sequence of maintenance visits, and determination of maintenance recall intervals. Maintenance therapy is often supportive in nature; hence, it is also known as supportive periodontal treatment (SPT). In this phase, patients must be made to understand the purpose of a maintenance program and the dentist must emphasize on the fact that the preservation of the teeth in question is dependent on it. Rationale for maintenance phase is to prevent or minimize the recurrence of periodontal diseases by controlling factors known to contribute to the disease process. The main aim of long-term therapy is to provide supervised control for the patient in order to maintain a healthy and functional, natural dentition for life.