10.22376/ijpbs.2019.10.1.p1-12 Volume 7 Issue 3 2016 (July - September) Water hyacinth(Eichhornia crassipes(Mart.) solms is a prolific freefloating aquatic macrophyte,monocotyledon of the family Pontederiaceae found in tropical and subtropical parts of the earth. It has received supreme interest in recent years owing to its constructivness in various fields.In the present study, evaluation of the antibacterial activity of methanolic floral extract at a concentration of (5,10,15 and 20 μg/ml) of the plant species, Eichhornia crassipes was carried out against Gram-positive bacteria (Staphylococcus aureus) and Gram-negative bacteria (Vibrio cholerae) by disc diffusion and minimum inhibitory concentration methods. The methanolic floral extract posses significant antibacterial activity at 20 μg/ml against the tested bacteria. Furthermore, gram positive bacterial species Staphylococcus aureus was found to be more sensitive as compared to gram negative. Therefore, the SHEHNAZ BEGUM T, VIJAYALAKSHMI M Eichhornia crassipes, Pontederiaceae, methanolic floral extract and Antibacterial activity. 1088-1091