Background: Probiotics are defined as ?live bacteria that naturally occur in certain foods as live micro-organisms which, when administered in adequate amount, confer a health benefit on the host.? They are safe for human consumption only when ingested in certain quantity, have beneficial effects on human health. Literature pertaining to the antimicrobial activity of probiotics is very limited. So this study was conceptualized to comprehensively report the antimicrobial potential of probiotics against periodontal pathogens. Objectives: To determine the effect of Lactobacillus Acidophilus and Streptococcus Salivarius probiotics on periodontal pathogens, (Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans and Prevotella intermedia) in-vitro using well diffusion method. Methods: Actinobacillus actinomycetemcomitans was cultured using tryptic soy-serum-bacitracin-vancomycin-fluoride (TSBVF) agar, Porphyromonas gingivalis was cultured using modified Wilkins-Chalgren (MWC) medium and Prevotella intermedia was cultured using brain heart infusion agar and incubated in Brewer-like anaerobic jars. Plates were inoculated with the probiotic strain of the lactobacillus acidophilus and Salivarius. Zone of inhibition was measured and compared with unaided eye using a Vernier caliper measuring the zone sizes. Results: Comparison of Zone of Inhibition after 24 hours and 48 hours using one way ANOVA test showed statistically significant results with inoculation of probiotics. Post hoc Tukey test compared within groups that showed the statistically significant difference between all organisms except for within A. actinomycetumcomitans and Prevotella intermedia. Conclusions: Lactobacillus and S. salivarius had inhibitory effect on periodontal pathogens in the oral microflora.