The corrosion inhibition by two synthesized Schiff -bases of bis-(2-hydroxy-3-methoxy)-l,6-diaminohexane salicyladimine and bis- (2-hydroxy)-1,6-diaminohexane salicyladimine was investigated by weight loss, Tafel polarization and AC impedance on low alloy steel in 1M HC1. The results show that these Schiff -bases act as anodic type inhibitors. The inhibition efficiency obtained from all method employed are in good agreement. Changes in impedance parameters (Rt and Cdt ) are indicative of adsorption of Schiff-bases onthe metal surface leading to the formation of protective film. Two Schiff-bases are found to adsorb on low alloy steel surface according to the Langmuir adsorption isotherm and thermodynamics calculations revealed that bis-(2-hydroxy-3-methoxy)-1,6-diaminohexane salicyladimine had larger adsorption constant and more negative free energy of adsorption than bis-(2-hydroxy)-1,6-diaminohexane salicyladimine.