GaAs 1 − x Bi x / GaAs multiquantum wells (MQWs) have been grown in the layer-by-layer mode of molecular beam epitaxy. A well-defined multilayered structure of the MQWs has been confirmed by cross-sectional transmission microscopy and high-resolution x-ray diffraction measurements. Photoluminescence has been observed from GaAs1−xBix/GaAs MQW at room temperature. The MQW structures have been confirmed to be thermally stable even after annealing up to 800 °C, although they need to be grown at a low temperature (350–400 °C) for Bi incorporation.