The aim of this work is to study corrosion behaviour of intumescent coating and the primer on steel substrate before and after a fire test. The coated steel substrates were subjected to fire in a furnace at 950oC for a variable duration ranging from 30, 45, 90 and 120 min. All coated steel substrates were also subjected to corrosion test by immersing them in 5 NaCl solution, for 15 min and three months duration using Electrochemical Impedance Spectroscopy (EIS). The specimen's impedance before fire test and before immersion was 4.37x108Ω.cm2. After 15 min exposure to NaCl, this value was reduced by 26, 53, 60 and 65 for specimens fired for 30, 45, 90 and 120 min, respectively. Further reduction in the impedance by 97.6, 97.8, 97.9 and 98.9 for samples fired for 30, 45, 90 and 120 min, respectively, were measured after three months in 5 NaCl immersion. © 2018 The Authors.