The high strain crack growth rate in isotropic Zircaloy-2 welds was measured using strain cycling with controlled limits of plastic strain. The crack growth rate was found to be a function of the longitudinal plastic strain range or the longitudinal elastic strain range as given by the expressions This isotropic crack growth is compared to low cycle fatigue and crack propagation tests performed on the anisotropic starting material from which the welded specimens were fabricated. The behavior of the weldments was consistent with that observed in the anisotropic plates. The crack growth rate in the welds was between the upper and lower extremes measured with different orientations of the anisotropic plates.