The hot deformation characteristics of pure molybdenum was investigated in the temperature range of 600sim1200°C and strain rate range of 0.01sim10.0/s using a Gleeble test machine. The power dissipation map for hot working was developed on the basis of the Dynamic Materials Model. According to the map, dynamic recrystallization (DRX) occurs in the temperature range of 1000sim1100°C and the strain rate range of 0.01sim10.0/s, which are the optimum conditions for hot working of this material. The average grain size after DRX is 5µm. The material undergoes flow instabilities at temperatures of 900sim1200°C and the strain rates of 0.01sim10.0/s, as calculated by the continuum instability criterion.