In this study, the effects of doping type and concentration on arsenic precipitation in low-temperature-grown GaAs upon postgrowth annealing at 600, 700, and 800 °C were investigated. Three undoped/Si-doped/undoped (i-n-i) regions and three undoped/Be-doped/undoped (i-p-i) regions were grown by low-temperature molecular beam epitaxy. The results show that arsenic precipitation is dependent on doping type and doping concentration. Arsenic depletion was observed in all Be-doped layers for all annealing temperatures. However, a “dual” arsenic precipitation behavior was observed in Si-doped layers: As accumulates in [Si]=2×1018 cm-3 doped layers, while it depletes in [Si]=2×1016 and 2×1017 cm-3 doped layers. We attribute this “dual” As precipitation phenomenon in Si-doped layers to the different depletion depths.