Antimicrobial resistance is now threatening the management of infections such as pneumonia, tuberculosis, malaria and AIDS.So at present scenario there is a great need for developing new anti-infective agents.Heterocycles are an inescapable and integral feature of numerous diverse branches of chemistry.The presence of heterocycles in all kinds of organic compounds of interest in biology,pharmacology, optics, electronics, material sciences.Among the heterocyclic compounds, five member heterocyclic moieties fused with aromatic ring system with various heteroatom like N, S, and O have possess wide spectrum of pharmacological activity.a variety of Schiff bases derivatives of sulfonamides have been successfully synthesized in appreciable yields and screened in vitro for their antimicrobial activities against both strains of Gram-positive and Gram-negative bacteria. Moreover, structure-activity relationship studies revealed that the 4-chloro benzaldehyde along with sulfamethoxazole Schiff base is more active as antimicrobial agent as compared to 2-chloro and 3-bromo derivatives but other derivative like salicyldehyde, anisaldehyde also possesses moderate activity.