The paper is focused on the evaluation of duplex ferritic-austenitic steel resistance to sulphide stress cracking (SSC). The testing was performed in accordance with the NACE TM 0177 Standard using tensile tests and four-point bending tests. The steel was always tested in two different structural states, in the as-received state (marked as AR), and after laboratory annealing by the mode of 800 °C/5h/air (marked as AN). Microstructure of steel in the AR state was formed by ferrite and austenite, the AN state was characterized by an disintegration of the part of ferrite and by formation of brittle σ phase. The aim of this study was to evaluate the effect of testing methodologies and changes of microstructural parameters of duplex steel resistance to SSC.