Absract In this research, first a hypoeutectic cast iron was cast according to method B of ASTM A367 standard chill test. Six gray cast irons samples with differen types of flake graphite as well as a mottled and a white cast iron were then cut from the casting. All samples were roughened to different values by mechanical abrasion and electroetching and their wetting angles and roughnesses were measured. After the last stage of the electroetching process, all samples were exposed to atmosphere for 4 weeks and their wettability was studied after 1, 2, 3 and 4 weeks of air exposure. Tafel polarization test was used to study the corrosion resistance of some of the samples and its correlation to their wetting angles. Microstructure and surface morphology of the samples were studied by optical and scanning electron microscopy in all roughening and oxidation stages. The results indicated that not only surface roughness but also the roughening method affected the surface wettability. Wettability of mechanically abraded cast iron surfaces with the same roughness was only affected by the type of phases present in the microstructure. Whereas, wettability of electroetched surfaces with the same roughness was further affected by the type and distribution of graphite flakes. increased with in all stages of electroetching and mechanical abrasion. Coarse A type and fine D type graphite gray cast iron samples in stages 1 and 2 of electroetching, fine E type graphite gray cast iron and mottled cast iron in stage 4 of electroetching and white cast iron mechanically abraded with 800 sandpaper followed Cassie-Baxter’s equation. Whereas, coarse A type graphite gray cast iron in stages 3 and 4 of electroetching and in all stages of mechanical abrasion, fine A type graphite gray cast iron in stages 1, 2 and 4 of electroetching and in mechanical abrasion by 80, 800 and 1200 grit sandpapers, coarse D type graphite gray cast iron in all electroetching stages and in mechanical abrasion by 80, 800 and 1200 grit sandpapers, fine D type graphite gray cast iron in all mechanical abrasion stages and in stages 3 and 4 of electroetching, coarse E type graphite gray cast iron in all mechanical abrasio and electroetching stages, fine E type graphite gray cast iron in stage 3 of electroetching and in mechanical abrasion by 80, 800 and 1200 grit sandpapers, mottled cast iron in mechanical abrasion by 320, 800 and 1200 grit sandpapers and white cast iron in all electroetching stages and in mechanical abrasion by 1200 sandpaper followed Wenzel’s equation. In other cases, the results did not fit to any of the models. Wettability of all the air exposed samples increased from values below 40? to above 90?. Polarization testes indicated that this could significantly increase their corrosion resistance. The reason for hydrophobicity of the air exposed samples was suggested to be related to formation of a low surface energy carbon layer by absorption of micro-organisms from the environment. Key words: Hydrophobicity, Contact angle, Gray cast iron, Surface roughness, Mechanical abrasion, Electroetching, Graphite type, Surface phases, Wettability model