Periodontal therapy aimed at regenerating lost periodontal structure. Growth factors of different platelet concentrates gained popularity in promoting soft and hard tissue regeneration. Efficacy of i–PRF is required to be explored. This was designed to evaluate the antimicrobial efficacy of i–PRF,PRF and blood. Blood sample obtained from 20 subjects and platelet concentrate was prepared using centrifugation protocol i.e, i–PRF and PRF. i–PRF considered as Group A, PRF considered as Group B and blood as Group C. Platelet count was done by manual counting method using Neubauer’s chamber. Antimicrobial activity examined by blood agar using well diffusion method by measuring zone of inhibition and quantifying inhibitory effect of platelet concentrate. Statistical analysis done by one–way ANOVA, P <0.05 considered statistically significant. Inhibition zone of bacteria around i–PRF(P ≤ 0.05) and PRF (P ≤ 0.05) was statisticaly significant compared to blood. Antimicrobial efficacy of i–PRF is better compared to PRF and control.