The profile of Rietveld method of structure refinement from powder diffraction data is widely used with neutron data and increasingly so with X-ray data. In the Rietveld method, the crystal structure is refined by fitting the entire profile of the diffraction pattern to a calculated profile. There is no intermediate step of extracting integrated intensities and so patterns containing overlapping peaks can be analyzed. With the development of high resolution diffractometers and high intensity sources such as Synchrotron sources, there has been a dramatic increase in the use of Rietveld refinement techniques. In this article, after describing the basic principles of the refinement procedure, selective applications of the use of Rietveld refinement technique are given.