By measuring the contact electrical resistance of the interlaminar interface of a unidirectional continuous carbon fiber epoxy-matrix composite during shear, the interlaminar shear process was monitored in real time. The resistance increased throughout the entire shear process for a low curing pressure, but decreased in the initial stage of shear for a high curing pressure. The resistance increase was due to delamination and strain in the interface region during shear. The resistance decrease observed for a high curing pressure is believed to be due to interlaminar rubbing and slight damage of the matrix between the fiber layers, and the consequent increase in the number of contacts between fibers of the adjacent laminae. The interlaminar displacement was negligible prior to shear failure.