InGaN epilayers with gallium fractions ranging between 0 and 0.48 have been studied by time-resolved photoluminescence. Layers containing low gallium fractions are associated with low PL emission intensity. For In 0.83 Ga 0.17 N layer, the luminescence decay is 100 times faster in the high energy part of the photoluminescence spectrum than on the low energy part, reflecting the hot carrier recombination process. This is confirmed by the significant blue shift of the photoluminescence spectra for short decay times compared to the time integrated spectrum. It takes about 10 ps for the carriers to reach an equilibrium temperature of 100 K.