X-ray diffraction intensity data from three compositions of zirconium-base alloys, viz. ZIRCALOY-2, ZIRLO, and Zr-25 pct Nb, having extensive application in nuclear industry were recorded using a PHILIPS PW 1730 X-ray diffractometer. Detailed studies using the recorded diffractometer data, keeping in view the recent trends in the powder diffraction analysis, were carried out with a view to evaluating the microstructural paramaters, including domain size, microstrain, faulting probability, and dislocation density. While faulting appears to be absent in all alloys, the average domain size and root-mean-square (rms) strain appear to be smaller compared to pure zirconium. However, both of these parameters, i.e., average domain size and rms strain tend to increase with the addition of Nb, as in ZIRLO, but display a diminishing trend with higher content of Nb, as is evident in the Zr-2.5 pct Nb alloy.