The inhibitoryeffect of isosorbidedinitratedrug(ISDN)on carbon steel was demonstrated in 1MHCl solution by weightloss, potentiodynamic polarization and electrochemical impedance measurements. The inhibition of ISDN drug is increased with increased concentration and minimize temperature. Data obtained from the polarization mention that ISDN drug is a mixed type inhibitor. The inhibition power of ISDN drug was explained on the basis of its adsorption on the carbon steel surface and the corrosion of carbon steel is lowered by adding ISDN drug. The adsorption of ISDN drug on to the surface of carbon steel in 1 M HCl obeys the Langmuir isotherm. Also, activation thermodynamic parameters such as Ea, ΔH* and ΔS* were calculated using Arrhenius and transition state equations and discussed.