Photoluminescence at 5K is used to measure the radiative recombination in a potential solar cell material -- polycrystalline GaAs. In some samples the elecron-hole pair recombination is extremely efficient, yielding luminescence intensities up to 40% of that of monocrystalline GaAs. These samples are characterized by a peak at approximately 1.49eV, which is similar to that observed in the monocrystalline GaAs. However in other samples a broad, less intense band at approximately 1.47eV is seen. © 1979 AIME.