CdSeS nanocrystals with different bandgap energies have been synthesized by the colloidal method. The solution blend of blue-, green-and red-emitting CdSeS nanocrystals, in appropriate proportions, showed strong white emission of different shades on excitation with a UV source. We observed that the CIE coordinate of the spectrum of a particular blend is independent of excitation wavelength. We also observed that the contribution of self-absorption in energy loss in the blend of CdSeS nanocrystals is not very significant. A white-light-emitting LED has been fabricated by coating a blend mixed with polymethylmethacrylate on a commercial UV-LED.