Bronze artifacts are generally covered with green or blue coloured corrosion products called patina, which not only enhances the good appearance of the bronze, but also helps to protect it. Because of the increased air pollution and acid rain the large collection of statues and works of art made from bronze exposed in the urban environment could be damaged. The increase of air pollution damages also archaeological bronze objects exposed or stored in a museum. This is why it is necessary to find ways to improve the protection that the patina gives to bronze. In order to preserve metal works from the aggressive atmosphere, organic inhibitors are often employed. The inhibiting effects of two imidazole derivatives (4-methyl-1-phenylimidazole and 4-methyl-1-(p-tolyl)imidazole) on artificial patina were examined. The results of these investigations have shown that both inhibitors studied improve the protective properties of bronze patina in simulated urban acid rains.