This paper aims to employ acoustic emission (AE) technique to detect and identify the level of damage resulting from reinforcing steel corrosion in reinforced concrete structures. Five reinforced concrete prism samples with a constant concrete cover (20 mm) were subjected to an accelerated corrosion test. The samples were corroded until reaching five different levels of theoretical mass loss: 1, 2, 3, 4 and 5% calculated using Faraday's law. The corrosion activity of the five samples was continuously monitored using attached AE sensors and a data acquisition system. The acquired AE signal parameters including AE signal strength, counts, energy, and number of hits were analyzed firstly to detect corrosion onset and secondly to predict the extent of damage as a result of corrosion propagation. The results obtained from AE monitoring were analyzed, evaluated, and compared to half-cell potential (HCP) measurements, and the amount of current passing with time. The analysis of these results involved comparing the AE cumulative signal strength (CSS) and each of the actual/theoretical percentages of mass loss, passed electrical current, and HCP readings. This analysis showed that CSS can be correlated to both HCP and electrical current at all degrees of damage from corrosion initiation up to 5% of mass loss. In addition, other AE signal parameters including number of hits, counts, and energy showed a significant increase in their cumulative values as the level of the theoretical mass loss, actual mass loss, and crack widths were increased. The results of this investigation confirmed that AE parameters (especially CSS) can be evaluated to detect corrosion earlier than other available nondestructive testing and evaluation techniques. Furthermore, it can be employed to represent the extent of damage occurring in reinforced concrete structures caused by corrosion of reinforcing steel.