We have studied the pressure and temperature dependence of the absorption edge of a 4-&mgr;m-thick layer of the alloyGa0.92In0.08As0.985N0.015.We have measured the hydrostatic pressure coefficient of the energy gap of this alloy to be 51 meV/GPa, which is more than a factor two lower than that of GaAs (116 meV/GPa). This surprisingly large lowering of the pressure coefficient is attributed to the addition of only ∼1.5&percent; nitrogen. In addition, the temperature-induced shift of the edge is reduced by the presence of nitrogen. We can explain this reduction by the substantial decrease of the dilatation term in the temperature dependence of the energy gap. ©1998 American Institute of Physics.