This report introduces a new definition for mild periodontitis, which is based on ≥2 interproximal sites with clinical attachment loss (AL) ≥3 mm and ≥2 interproximal sites with probing depth (PD) ≥4 mm (not on the same tooth) or one site with PD ≥5 mm. This definition aims to better describe the overall prevalence of periodontitis in populations. The authors compared the proposed definition with previously reported definitions for moderate and severe periodontitis in a sample of 456 adults aged ≥35 years. The addition of mild periodontitis increased the total prevalence of periodontitis by approximately 31% compared to the prevalence of severe and moderate disease. The study concluded that the total periodontitis should be based on the sum of mild, moderate, and severe periodontitis. The report also discusses the comparison between the CDC–AAP and European case definitions, highlighting their strengths and limitations in terms of sensitivity, specificity, and agreement. The findings suggest that the proposed definition for mild periodontitis can improve the accuracy of periodontitis prevalence estimates and is valuable for public health surveillance and research.This report introduces a new definition for mild periodontitis, which is based on ≥2 interproximal sites with clinical attachment loss (AL) ≥3 mm and ≥2 interproximal sites with probing depth (PD) ≥4 mm (not on the same tooth) or one site with PD ≥5 mm. This definition aims to better describe the overall prevalence of periodontitis in populations. The authors compared the proposed definition with previously reported definitions for moderate and severe periodontitis in a sample of 456 adults aged ≥35 years. The addition of mild periodontitis increased the total prevalence of periodontitis by approximately 31% compared to the prevalence of severe and moderate disease. The study concluded that the total periodontitis should be based on the sum of mild, moderate, and severe periodontitis. The report also discusses the comparison between the CDC–AAP and European case definitions, highlighting their strengths and limitations in terms of sensitivity, specificity, and agreement. The findings suggest that the proposed definition for mild periodontitis can improve the accuracy of periodontitis prevalence estimates and is valuable for public health surveillance and research.