Major advances in the knowledge about the aetiopathogenesis of aggressive periodontitis (AgP) have been achieved. An ever increasing number of scientific articles related to AgP are published every year contributing significantly to the knowledge of this unique and complex disease. AgP has been classified into localised and generalised forms based on their extent and disease progression with distinct clinical and radiological features. A classification of AgP based on severity (mild, moderate and severe) exists; however, it is not easily applicable. Therefore, studies on AgP do not categorise the disease based on severity. A disease staging index for AgP is proposed based on clinical and radiological features, as well as risk factors. Based on the presence or absence of risk factors confirmed by longitudinal studies, cases of AgP can be divided into low risk, medium risk and high risk profiles for disease progression. Clinicians can devise a broad treatment plan for their AgP cases based on this staging. More frequent recall intervals are proposed for patients at medium and high risk for disease progression. Ten cases of AgP with 10-year follow-up were used to validate the staging index by retrospectively assigning prognosis and associating it with tooth loss. The use of this staging by researchers would increase external validity of research on AgP. Long-term analysis of AgP cases are needed to validate this staging index longitudinally.