Aegle marmelos is a medicinal herb belongs to the family Rutaceae, used for antimicrobial screening against selected four pathogenic microorganisms - Escherichia coli MTCC40, Salmonella typhi MTCC3216, Proteus vulgaris MTCC428 & Staphylococcus aureus MTCC3160. Bark of Aegle marmelos was extracted in ethanol and petroleum ether through cold and hot extraction method. For control petroleum ether, ethanol and Ampicilin were used. Zone of Inhibition and Minimum Inhibitory Concentration were determined by Disk Diffusion Method and Broth (Tube) Dilution Method respectively. Results of these two methods showed antimicrobial effect against all the above four microorganisms.