Acidization is an oil reservoir stimulation technique for increasing well productivity. Hydrochloric acid, HCl, is used in oil and gas production to stimulate the formation. The acid treatment occurs through steel tubes. The process requires a high degree of corrosion inhibition. The present study deals with the evaluation of the effectiveness of the new synthesized compound namely; 6-methyl-5-[m-nitro styryl]-3-mercapto-1,2,4-triazine as corrosion inhibitor for mild steel in 12% HCl solution at 50 degrees C using various chemical and electrochemical techniques. The results showed that anodic dissolution of mild steel was remarkably decreased. The strong adsorption ability of this new synthesized compound can be attributed to the presence of multiple adsorption centers of nitrogen as well as pi-donor moieties. (C) 2007 Elsevier Ltd. All rights reserved.