Prognosis is the clinical forecast of the probable course and final outcome of a disease. Prognosis is the basis on which the clinician makes recommendations and is a key factor in aiding the patient in choosing a course of treatment. It would be preferable to rely exclusively on an evidence-based model for our entire decision making, including establishing a prognosis. Periodontal disease is complex and variable disease which can be influenced by individual systemic factors. Tooth related factors, systemic factors, and other patient related factors are taken into consideration to determine the prognosis.