Objective: Chronic periodontitis (CP) is a common inflammatory disease that causes destruction to the supporting tissues of the teeth. Many treatment modalities tried to stop disease progression. Platelets rich plasma (PRP) is one of the regenerative methods that are used in adjunct to conventional periodontal treatment. The aim of this study was to evaluate the anti-inflammatory effect of PRP by monitoring the lymphocyte count before and after its application to the periodontal pocket. Methods: Around 20 patients with CP and a pocket depth equal to or deeper than 4 mm, subjected to scaling, root planning, and PRP injection into the pocket. Lymphocyte count measured before and after 1 month from PRP application. Clinical periodontal parameters are taken in 2 visits with customized stent fabrication. Results: All clinical periodontal parameters show a reduction in their value following one month after PRP application. There was a marked reduction in the lymphocyte count; mean (2.47 ± 0.91) to (1.94 ± 0.77) after the treatment with PRP. Conclusions: In addition to its traditional uses, PRP has a great role in the periodontal treatment by its anti-inflammatory effect.