Two-phase oil-water flows are commonly found in the oil industry. The occurrence of water can lead to internal corrosion of the metallic pipes besides other possible degradation phenomena such as environmentally assisted cracking. For instance when water phase is fully entrained into the oil phase internal corrosion of carbon steel is not likely to occur. Full entrainment of water into oil majorly depends on operating flow conditions physicochemical properties of both fluids and phase wetting characteristics of the pipe material. This paper presents a set of hydrodynamic and phase wetting criteria to assess if free water will be in contact with internal pipe walls; and thus to primarily determine corrosion risk. Experimental data of oil-water pipe flows is also shown and compared with theoretical calculations.Key words: Oil-water flow; entrainment; phase wetting; corrosion