Recently InxGa1-xN/GaN heterostructures and quantum wells (QWs) have gained immense importance in the application of III-V nitride materials. Reported values of the ratios of conduction band offset to valence band offset for InxGa1-xN/GaN QW structures, Delta E-c:Delta E-v, vary widely from 38:62 to 83:17. While trying to explain the unusual shifts in the photoluminescence (PL) spectra, obtained from InXGa1-xN/GaN QW structures, it has been found that a band offset ratio, Delta E-c:Delta E-v=55:45, explains all the experimental data precisely. In this paper detailed theories, procedures, results and discussions to establish the newly estimated band offsets will be presented. (c) 2006 Elsevier B.V. All rights reserved.