Schiff bases were prepared by using 4-amino-3-hydroxy benzoic acid, namely (E)-3-hydroxy-4-((4-nitrobenzylidene)amino)benzoic acid, (E)-3-hydroxy-4-((2-hydroxy-3-methoxybenzylidene)amino)benzoic acid, (E)-4-((5-bromo-2-hydroxybenzylidene)amino)-3-hydroxybenzoic acid and (E)-3-hydroxy-4-((4-hydroxy-3-methoxybenzylidene)amino)benzoic acid. 4-nitrobenzaldehyde, Ortho-vanillin, 5-Bromosalicylaldehyde and vanillin are used for the preparation of Schiff bases. 4-amino-3-hydroxy benzoic acid(0.002m) was dissolved in ethanol and mixed with aldehyde(0.002m) dissolved in ethanol ,mixed solution stirred for 15 minutes at 60o c and gives solid products. Synthesized Schiff bases were structurally characterized based on IR,NMR,HRMS and elemental analy-sis. The synthesized Schiff bases were screened for their biological activity against bacterial species Gram –ve bacte-ria (Escherichia coli), Gram +ve bacteria (Staphylococcus aureus) and fungi(aspergillusniger).