Crude fatty acid extract of soil Streptomyces sps on the biofilm formation by Streptococcus pyogenes ATCC 19615 was investigated. Totally, 25 Streptomyces sps were isolated identified from the soil samples collected from Nilgiris hill station. All the isolates were subjected to hydrogen peroxide assay, fatty acid extraction and antibiofilm assay. The fatty acid extracts of S8, S9, and S15 inhibited S. pyogenes at MIC 10 µg/ml. The BIC was observed as 84.6% , 96.41%, 80.5% at 50 µg/ml concentration. Streptolysin S assay showed that the crude lipid extracts have the capability of inhibiting the Streptolysin S activity. There were changes in extracellular protein of the pathogen exposed to the S8, S9 and S15 crude fatty acid extracts (50 µg/ml) at the range of 100-120 kDa which elucidates that the fatty acid extracts have a significant role in altering the extracellular protein which might be responsible for virulence of the pathogen.