The effect of Mn/S ratio on hot ductility of Bi bearing steels has been investigated at the temperatures ranging from 950 to 1250. The hot ductility, measured as the reduction ratio of area, was found to depend on the Mn/S ratio and test temperature to provide the largest hot ductility at the ratio of 3.903 at 1200 . The hot workability of Bi bearing free cutting steels seems to depend greatly on the size, volume fraction, and type and distribution of inclusions. In addition, hot deformation behavior of Bi bearing free cutting steel has also been characterized by constructing a processing map developed on the basis of the dynamic material model. A series of hot compression tests has been carried out at the temperatures ranging from 950 to 1250 under the strain rate ranging from 10-3 /s to 102 /s.