Prognosis is an integral part of the periodontal practice because it directly influences treatment planning. However, there is limited direct evidence in the literature regarding the assignment of periodontal prognosis. There are several important concepts to consider in developing a system of periodontal prognosis. Traditional systems are based on tooth loss and may have limited use for patient management. On the other hand, prognosis can be based on stability of the periodontal supporting apparatus, which is influenced by more evidence-based factors and may be more useful for patient management. Other important concepts include the timing of the projection (short and long term) and the consideration of individual teeth versus the overall dentition. Historically, several authors have formulated and investigated their own prognostication systems. Results were variable, but they generally showed that systems based on tooth loss were unpredictable over the long term. Therefore, the purpose of this report is to review relevant literature and propose a new periodontal prognostication system.