The corrosion rate of rebar in concrete traditionally has been determined using polarization methods such as the potentiodynamic technique, galvanostatic pulse technique, potentiostatic pulse technique, and, in some cases, the electrochemical impedance spectroscopy technique in laboratory applications. These techniques are very slow, and all require having an electrical connection to the rebar, which makes them impractical in the field. In this paper, the recently developed technique of Connectionless Electrical Pulse Response Analysis (CEPRA) will be introduced. The CEPRA method, which eliminates the need to have a rebar connection, is based on the concept that the voltage response of the corroding rebar is different from that of the noncorroding rebar once subjected to variable frequencies of an AC current applied on the concrete surface using the four-probe Wenner array configuration. However, direct measurement of the low-frequency impedance of rebar in concrete is very time-consuming and vulnerable to noise interruption; hence, in the CEPRA method, a narrow current pulse is applied for a short period of time (for a couple of seconds). Using the recorded voltage and the applied current, the low-frequency impedance response of rebar in concrete can be extracted, which can be used to determine the state of corrosion in reinforced concrete structures. The details of the CEPRA technique and equivalent electrical circuit models will be discussed in this paper. Laboratory and finite element modeling results will be presented to compare the traditional corrosion rate measurement techniques with the CEPRA method.