This paper describes the piezoresistance behavior in CFRP cross-ply laminates with transverse cracking loaded in tension. The resistance change due to transverse cracking and the gage factor (the rate of resistance change per mechanical strain) for each transverse crack density were experimentally measured during loading/unloading cycles. The resistance change-strain curves in the unloading/ reloading processes show the bilinear behavior where two gage factors are defined as the slopes of the bilinear curve. The residual resistance change after full unloading increases almost linearly with the mechanical strain while the gage factors do not always increase with the strain. The residual resistance change and gage factors are associated with transverse crack density on the basis of an equivalent resistance circuit.