Purpose: To compare the total and differential leukocyte counts in the peripheral blood of generalised aggressive periodontitis patients with that of periodontally healthy subjects in a central Indian population. Materials and Methods: Seventy-five patients with generalised aggressive periodontitis and 63 periodontally healthy subjects were enrolled for the purpose of the study. All participants received a full-mouth periodontal examination in which probing depth and clinical attachment level were recorded. The haematological variables analysed included total leukocyte count, neutrophil count, lymphocyte count, monocyte count, neutrophil percentage, lymphocyte percentage, monocyte percentage and platelet count. Results: The patient group showed a significantly higher total leukocyte count (7.62 ± 1.70 x 109 cells/l, p = 0.008), neutrophil count (5.06 ± 1.47x109 cells/l, p 0.001) and neutrophil percentage (70.61 ± 8.73, p 0.001), as well as a significantly lower lymphocyte count (1.82 ± 0.65 x 109 cells/l, p = 0.002) and lymphocyte percentage (26.55 ± 8.05, p 0.001) compared to the control group. Logistic regression analyses showed significant associations between aggressive periodontitis and elevated total leukocyte (p = 0.012) and neutrophil counts (p = 0.001). Conclusion: The findings of the present study suggest that patients with generalised aggressive periodontitis might also demonstrate a systemic inflammatory response, as evidenced by increased leukocyte counts. This systemic inflammatory response observed in patients with generalised aggressive periodontitis may be associated with an increased risk for cardiovascular diseases. Schlagwörter: aggressive periodontitis, cardiovascular diseases, inflammation, leukocyte count, neutrophils