In this study thirteen new substituted/nonsubstituted benzalhydrazone V derivatives of 3-(6-substituted-3(2H)-pyridazinon- 2-yl)propionohydrazide derivatives IV were synthesized as acetylcholinesterase and butyrylcholinesterase inhibitors. The structures of compounds V were elucidated by IR, 1H-NMR and MASS spectra. The acetylcholinesterase (AChE) and butyrylcholinesterase (BChe) inhibitory activity of V derivatives was measured using Ellman's method. Only (4-chlorophenylbenzal)hydrazone derivatives of 3-(6-(4-fluorophenyl)-3(2H)-pyridazinon-2-yl)propionohydrazide Vi showed an excellent inhibitory effect against AChE. In addition, Vi showed a significant inhibitory effect against BChE.