The environmental friendly inhibitor system L-Serin e-Zn 2+ , has been investigated by weight loss method. A synergistic effect exists between L-Serine and Zn 2+ system. The formulation consisting of 250 ppm of L -Serine and 50 ppm of Zn 2+ offers good inhibition efficiency of 98%.Polarizat ion study reveals that this formulation functions a s anodic inhibitor. AC impedance spectra reveal that a protective film is formed on the metal surface. T he FTIR spectra study leads to the conclusion that the Fe 2+ - L-Serine complex formed on anodic sites of the me tal surface controlled the anodic reaction and Zn(OH)2 formed o n the cathodic sites of the metal surface controlli ng the cathodic reaction. A suitable mechanism of corrosio n inhibition is proposed based on the results obtai ned from weight loss study and surface analysis technique. S ynergism parameters have been calculated. They are found to be greater than 1 suggesting that a synergistic effect exists between L-Serine and –Zn