Photoluminescent (PL) properties of heavily carbon- and zinc-doped GaAs were investigated for concentration from 8 X 10(17) to 2.3 x 10(20) cm-3 and temperature from 300 K to 20 K. Both a band-to-band (B, B) peak and a band-to-acceptor (e, A) peak appeared at 300 K for the heavily p-type-doped GaAs PL spectra, even in degenerated GaAs. The variation of the intensities of the (e, A) peak and (B, B) peak with concentration and temperature was investigated, and the change in position of the two peaks at various concentrations and temperatures was observed. The rapid increase in linewidth with increasing concentration due to the appearance of a shoulder peak was also studied; this behavior is different from that of the shoulder peak in the PL spectrum from Zn-doped crystal.