As part of its efforts to maximize process efficiency and decrease energy requirements in mineral processes, the federal Bureau of Mines has investigated methods for beneficiating bastnasite ores from Mountain Pass, CA. The results of a bench-scale study on the flotation of bastnasite ore are presented. Flotation at a pulp temperature of 40 deg to 45 deg c yielded a cleaner concentrate containing 58.7 pct re2o3 at a rare-earth recovery of 67 pct. These results are comparable to those reported for the commercial beneficiation method in which the pulp is heated to boiling before flotation. An attempt was also made to recover a barite flotation concentrate from the bastnasite rougher tailing. Concentrates containing only 70 pct barite were obtained.