Non-equilibrium electron distributions and energy loss rate in a metal-organic chemical vapor deposition-grown In x Ga 1− x As 1− y N y ( x=0.03 and y=0.01) epilayer on GaAs substrate have been studied by picosecond Raman spectroscopy. It is demonstrated that for electron density n≅10 18 cm −3 , electron distributions can be described very well by Fermi–Dirac distributions with electron temperatures substantially higher than the lattice temperature. From the measurement of electron temperature as a function of the pulse width of excitation laser, the energy loss rate in In x Ga 1− x As 1− y N y is estimated to be 64 meV/ps. These experimental results are compared with those of GaAs.