The use of Mo-Si-B alloys as structural materials at elevated temperatures will be dependent upon both environmental resistance and structural capability. Previous processing efforts on Mo-2Si-1B (wt%) alloys were successful in producing material with a microstructure consisting of discrete Mo5SiB2 and Mo3Si intermetallics within an a-molybdenum matrix. This material possessed attractive mechanical properties and enhanced environmental resistance. Efforts at further improving environmental resistance have been concentrated on alloys near the Mo-3Si-1B (wt%) composition. These alloys rely on a high volume fraction of intermetallic for inherent oxidation resistance, while a low volume fraction of intermetallic within a continuous metal matrix is ideal for meeting demanding mechanical property requirements. Recent improvements in the processing of Mo-3Si-1B alloys have demonstrated properties approaching those of the model Mo-2Si-1B material. The effect of processing on the microstructure and mechanical properties of both Mo-3Si-1B and Mo-2Si-1B alloys will be discussed.