In the present study, six new derivatives of PYridazinone were synthesized and evaluate their anti-bacterial activity. The experimental work involves the synthesis of benzoyl propionic acid (a), then 6-phenyl-2,3,4,5-tetrahydro pyridazin-3-one (b) which was then condensed with various, aldehydes to form respective derivatives, AH the synthesized compounds were identified by IR, 1HNMR and antimicrobial activity was performed on the compounds synthesized against Staphylococcus aureus (MTCC 737), Staphylococcus epidermidis (MTCC 3615), Pseudomonas aeruginosa (MTCC 424) and Escherichia coli (MTCC 1687)