A cold-rolled, commercial pure aluminium and three aluminium-magnesium alloys (containing, respectively, 1 wt%, 3 wt% and 5 wt% magnesium) were studied by X-ray-diffraction (XRD) profile analysis. The investigated equivalent plastic deformations of the materials were ranged between 0.1 and 5.0. With increases in the amounts of magnesium, the diffraction peaks widened. For each alloy, the peak width (which gives first information from the analysis) increased for low deformation ratios and reached a maximum value, ds(max), and then it decreased or stabilized. The ds(max) value increased with increases in the amount of magnesium in the alloys and ranges for equivalent deformation <(epsilon)over bar> = 0.3 and 1.5. The results of the X-ray profile analysis have been correlated with previous observations by transmission electron microscopy (TEM), and they have been successfully used to quantify the microstructural features of the alloys.