Corrosion resistance behaviour of 12Cr martensitic stainless steel was evaluated in different hydrochl oric acid and the acid chloride concentrations. Corrosion inhibit ion of the tested samples in 1M HCl was also evalua ted using potassium dichromate. The experiments were performe d at ambient temperature using potentiodynamic pola rization measurement. This paper reports the observed electr ochemical response of the experimental tests. Diffe rent concentrations of the test media were used with sod ium chloride addition. Tafel and polarization resis tance techniques were used to estimate the corrosion rate , the polarisation resistance and inhibition of the alloy samples tested. The results obtained showed some magnitude of corrosion susceptibility for the stainless steel at higher HCl concentrations and also in the acid chloride test m edia. Effective corrosion inhibition was also exhib ited on the tested samples.