This research aims mainly to investigate: (1) corrosion of steel in cracked concrete, (2) effect of crack width and (3) effect of water-to-cement (w/c) ratio and cover depth. The corrosion phenomena in single-crack and multi-crack specimens were observed by electrochemical methods and visual examination. The test also included the additional variables of steel stress (crack width), w/c ratio and cover thickness. Steel at every crack of the single-crack specimens corroded. For a multi-crack specimen, there is a tendency that the widest crack in the specimen induced corrosion earliest. Consequently, corrosion at the crack delayed and suppressed corrosion at the other cracks. For cracked specimens with 20-30 mm cover depth, considering only the cracks those first induced corrosion, crack width affected corrosion at the earlier stage than at the latter stage. Finally, w/c ratio had a greater effect on corrosion in cracked specimen than cover depth.(A) For the covering abstract of the conference see IRRD 831449.