The use of vapour phase corrosion inhibitors (VPIs) is one of the most effective and convenient methods for preventing corrosion of metallic articles and equipments during storage and transportation. In the present investigation, diethylamine phosphate (DEAP) has been synthesized and its inhibitive performance was evaluated through accelerated vapour phase corrosion test and electrochemical methods such as Tafel polarization and impedance measurements using three electrode type atmospheric corrosion monitor (ACM) at 100% RH in a confined space. The potentiodynamic polarization studies show that the corrosion inhibition of carbon steel by DEAP is predominantly under cathodic control. The performance of VPI in different environments such as chloride, sulphur dioxide and field exposure test has also been evaluated. It was found that the DEAP offered more than 90% protection against corrosion of carbon steel under normal atmospheric conditions. (c) 2006 Elsevier B.V. All rights reserved.