Co, Ni and Cu complexes have been prepared by reacting metal chloride with 4-chlorobenzaldehyde oxime, 4-methylbenzaldehyde oxime, 4-nitrobenzaldehyde oxime, 4-chlorobenzaldehyde semicarbazone, 4-methyl- benzaldehyde semicarbazone, 4-nitrobenzaldehyde semicarbazone, 4-chloro benzaldehyde phenylhydrazone, 4-methylbenzaldehyde phenyl hydrazone and 4-nitrobenzaldehyde phenylhydrazone and their antibacterial activity have been studied and compared with their ligands against E. coli which gave significant results of activity.