A current-perpendicular-to-the plane magnetoresistive sensor with a self-pinned in-stack longitudinal bias structure is provided comprising a ferromagnetic bias layer formed of material having a negative magnetostriction coefficient and a spacer layer for antiparallel coupling to a free layer. The negative magnetostriction of the bias layer interacts with the lapping-induced stress anisotropy of the sensor stack to provide strong pinning of the magnetization of the bias layer in a direction parallel to the ABS and antiparallel to the direction of the magnetization of the free layer. Magnetostatic coupling of the bias layer magnetization with the free layer provides a longitudinal bias field to stabilize the free layer magnetization.