10.22376/ijpbs.2019.10.1.p1-12 Volume 4 Issue 1 2013 (January - March) This article describes the antimicrobial properties of lessThan i greaterThan Argemone mexicana lessThan /i greaterThan a plant that grows in tropical and subtropical regions. The antimicrobial efficacy of different solvent extracts (Ethyl acetate, methanol and aqueous) of lessThan i greaterThan Argemone mexicana lessThan /i greaterThan leaves against different pathogenic microorganisms was investigated using the disc diffusion method. The aqueous and methanolic extracts exhibited potent antibacterial activity against two Gram positive ( lessThan i greaterThan Enterococcus fecalis, Staphylococcus aureus) lessThan /i greaterThan and two Gram negative ( lessThan i greaterThan Klebsiella pneumoniae, Proteus mirabilis) lessThan /i greaterThan bacteria and moderate antifungal activity against lessThan i greaterThan Aspergillus fumigatus lessThan /i greaterThan and lessThan i greaterThan , Cryptococcus neoformans lessThan /i greaterThan . The zone of inhibition was found to be in the range of 10.0 - 25.0 mm when tested at a concentration range of 75 - 500 μg/disc. Differences in the antimicrobial activity can be attributed to the presence of different phytochemicals present in these extracts. Phytochemical analysis of different fractions that have shown efficacy may contribute to the development of new antimicrobial agents. C. KRISHNA KUMARI, C. SHANMUGA REDDY, Y. RAJA RATNA REDDY,D. NARAPA REDDY AND C. DAMODAR REDDY Argemone mexicana, Antimicrobials, Disc diffusion method, Zone of inhibition, Phytochemicals, Pathogenic bacteria. 536-541