Based on morphological, biochemical and 16s rRNA gene sequencing a newly isolated endophytic bacterium from the Musa balbisiana (banana) was identified as Bacillus siamensis and designated as BE 76. There are fifteen bacterial isolates were screened out for their productivity of Indole acetic acid by spectrophotometeric method. Out of these isolates BE-76 isolate showed high amount of Indole acetic acid production supplemented with and without L tryptophan in medium. The productivity of IAA from BE-76 isolate supplemented with and without L tryptophan in medium was confirmed by High-Performance Liquid Chromatography (22.74, 20.46 ppm, respectively at 280 nm) for more accuracy. This bacterium will further be useful for preparation of liquid bioinoculant to enhance the banana production as well as for ecofriendly and sustainable agriculture.