A study of plastic strain controlled fatigue of copper and copper-zinc shows that polycrystalline Cu-30%Zn does not display true cyclic saturation and that texture has a major effect on the cyclic stress-strain (CSS) behaviour, whereas grain size has a minor effect. The self-consistent Sachs estimate of the CSS curve for polycrystalline Cu-30%Zn lies within 20% of the experimental curve for plastic strain amplitudes up to about 5 [times ] 10 [ m i n u s ] 3 , as compared with 1 [times ] 10 [ m i n u s ] 3 for copper. The increased range of validity of the Sachs model is correlated with slip planarity.