This study aims to investigate the effect of initiator concentrations of polymeric derivatives of 2-vinylpyridine, P(2VP) as corrosion inhibitors of mild steel in CO2-satured brine solution. Polymerization of the monomer was conducted using hydrogen peroxide initiator with four different concentrations of 0.25; 0.33; 0.50; and 0.80 mole, to produce four oligomers referred to as P(2VP)A, P(2VP)B, P(2VP)C, and P(2VP)D, respectively. A series of corrosion experiments was conducted to determine the corrosion rate of the mild steel using weight loss and linear polarization resistance (LPR) methods. The effect of inhibitor concentration, and temperature, on the corrosion rate was also investigated. The oligomers synthesized were found to have different physical appearance. Two oligomers, the P(2VP)A and P(2VP)B, were found as yellow viscous liquids, with O(2VP)B is more viscous than P(2VP)A, while the other two oligomers, P(2VP)C and P(2VP)D exist as yellow solids. The experimental results reveal that the use of monomer led to higher corrosion rate compared to that of blank experiment, but reduced corrosion rate was achieved with the use of the oligomers. P(2VP)A as an oligomer synthesized with the lowest concentration of H2O2 initiator inhibited the corrosion more effective than the higher concentrations. It was also found that the higher the concentration of the oligomer, the better the protection. For temperature, the opposite is true, indicating that the oligomer was physically adsorbed onto the surface of mild steel.