Imidazoline derivates have been synthesized from soybean oil fatty acids and some amines (diethylenetriamine (A), triethylenetetramine (B) and tetraethylenepentamine (C)) by condensation polymerization method. The three samples were analyzed by Fourier Transform-Infrared (FT-IR) and Potentiodynamics. The purpose of experiment is to synthesize the imidazoline from soybean oil fatty acid (kind of fatty acid) as environmentally friendly corrosion inhibitor. Data of FT- IR shows several peaks with a ring imidazoline already formed. Analysis of the ability as corrosion inhibitor was performed using Potentiodynamic Polarization and Open Circuit Potential (OCP) method with 5 % NaCl at room temperature. It shows that imidazoline derivates SOFA/DETA Imidazoline (IM A) give IE 90.34 % in mild steel. Moderate concentration of SOFA/TEPA Imidazoline (IM C2) has good long terms corrosion inhibitor for mild steel at 5 wt.% NaCl solution at room temperature. It can be concluded that imidazoline derivatives products can be used as alternative corrosion inhibitor on mild steel.