This paper presents the self-assembly of 1-(3-aminopropyl) imidazole (API) monolayer on the copper surface to study the inhibition effect of the API against copper corrosion in 3% NaCl solution. The optimum concentration and assembling time for the assembly of API on copper were ascertained using electrochemical impedance spectroscopy (EIS). It was found that the API self-assembled monolayer (SAM) was formed with the concentration of 1.0mM of API at 24h assembling time and the maximum inhibition efficiency that could be achieved was 93.10%. The API SAM on copper was characterized by Fourier transform infrared spectroscopy (FT-IR), energy dispersive X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and water contact angle measurement (WCA). The presence of N and C signals in the XPS and EDX, show that the API molecules successfully anchor on the copper surface which demonstrates formation of API SAM on the copper surface. Corrosion protection capability of the copper modified with API was evaluated by the electrochemical polarization study (EPS) and scanning electron microscopy (SEM). The results of electrochemical and SEM analysis revealed that the API modified copper showed better corrosion protection in 3% NaCl solution.