New characterization data are presented for the deep‐level defects observed in photoluminescence (PL) spectra of InGaAs near 0.1 eV within the band gap. The literature regarding these defects is summarized and compared to the results of this study. Defects are seen to be present in In‐rich, Ga‐rich, and lattice‐matched In1−xGaxAs/InP epilayers. The PL spectra vary depending on alloy composition and crystal growth conditions. PL spectra at 77 K for 0.46<x<0.50 and input laser powers of 9–18 W/cm2are given for material grown by organometallic vapor phase epitaxy. Hall mobility and Auger electron specroscopy data are also give for these epilayers. The cause of the defects is unknown, but it is not InP substrate doping or growth impurities. Imperfect arsenic incorporation may be involved, as evidenced by the dependence of PL spectra on growth conditions.