This paper presents the results of research into corrosion behavior of duplex stainless steel (DSS) 2205 in 0.6M NaCl solution (synthetic seawater) and Postgate B+ microbiological medium, under abiotic and biotic conditions. The effect of the presence of sulfate reducing bacteria (SRB) on corrosion of DSS 2205 in comparison to abiotic conditions is studied and discussed. electrochemical tests included the measurement of open circuit potential (OCP) and anodic polarization scans. These indicated that electrochemical behavior of DSS 2205 in the biotic condition is considerably different by comparison to that in the abiotic environment. In particular, the resistance to pitting corrosion of DDS 2205 decreases with increasing of time exposure to SRB environments.