Abstract: Inhibitor for mild steel derived from carbethoxythiazole namely 2-amino-4-methyl-5-carbethoxythiazole was synthesized and the chemical structure was elucidating by fourier transform in frared and nuclear magnetic resonance spectroscopies. The inhibition efficiency for 2-amino-4-methyl-5-carbethoxythiazole to inhibit the damage effects for mild steel of corrosion in 1 M hydrochloric acid solution was figured and was 82.5% regarding to weight loss technique. Scanning electron microscopy was used as a confirmation of ability of 2-Amino-4-Methy l-5-Carbethoxythiazole (AMC) to inhibit the corrosion of specimens of mild steel surface. The standard free energy of adsorption and adsorption equilibrium constant were calculated and the adsorption of 2-amino-4-methy l-5-carbethoxythiazole on surface of mild steel was obey adsorption isotherm of Langmuir. To proof the methodological findings, density function theory at the B3LYP/6-311+G** level of theory was used to calculate highest occupied with lowest unoccupied molecular orbitals energies and dipole moment.