Aggressive periodontitis, which is characterized by the rapid rate of progression of periodontal disease in the absence of a large amount of bacterial plaque or present stone, affects healthy individuals under 30 years of age. Objective: The aim of this study was to determine the prevalence of aggressive periodontitis among high school students. Study Design: A Retrospective Study. Location and Duration: In the Dental department of Nishtar Hospital Multan for one year duration from July 2017 to June 2018. Methods: 780 students attending high school were randomly selected. Probing depths were measured in 6 permanent incisor teeth and first molars each individual. Those with a depth of pocket greater than 4.5 mm were invited to participate in the next stage of the study in which periapical and bitewing radiographs were taken. Individuals with evidence of radiographic bone loss completed clinical and radiographic examinations. The prevalence of aggressive periodontitis was determined. Fisher's exact test was used to determine 4 significant differences between sex groups. Data were analyzed using the 18th version of SPSS. Results: The probing depth was> 4.5 mm in 39 of 780 patients. Thirty-four of these individuals presented a subsequent examination, which led to the diagnosis of aggressive periodontitis localized in 6 subjects (0.77%), 4 girls (0.86%), and 2 children (0.63%). There was no significant difference between boys and girls. We could not find cases of generalized aggressive periodontitis. Conclusion: The results of this study revealed that 0.77% of the population studied was diagnosed with localized aggressive periodontitis. This figure is similar to that reported for the European and North American population. Key words: aggressive periodontitis, localized aggressive periodontitis, generalized aggressive periodontitis, prevalence.