The goal of this work is to determine the biofilm colonization on the surface of superduplex stainless steel S32750 by Sulfate Reducing Bacteria (SRB) in a flow loop at constant flow rate and room temperature, exposed to artificial sea water. The duplex stainless steel has been widely used as material for offshore applications due to their excellent corrosion resistance in chloride environments, compared with austenitic stainless steel. At high concentrations these sulfides are known to adsorb and catalyze anodic dissolution and hence facilitate pitting. The samples of S32750 were exposed to flowing conditions for 15 and 35 days. Other 316 stainless steel coupons were exposed under the same time in order to compare with superduplex. The physical and chemical characteristics of a solid surface affect biofilm formation in flowing systems. Surface roughness affects bacterial adhesion. The degree of surface roughness may well be a critical factor in biofilm development. Some coupons were ground and others were polished (6 μm e 1 μm - diamond paste). The bacterial cells were quantified using most probable number (NMP) method. It was also quantified the total sulfide, the organics acids and sulfate depleted. Biofilm morphology, surface roughness and pitting formation were explored.