In this study, the consolidation behavior and hardness of commercially available molybdenum powder were investigated. In order to analyze the compaction response of the powder theoretically, and elastoplastic constitutive equation based on the yield function presented by Shima and Oyane was applied to predict the compact density under uniaxial pressure from 100 MPa to 700 MPa. The compacts were sintered at 1400-1600 degrees C for 20-60 min. The sintered density and grain size of molybdenum were increased with increasing the compacting pressure and processing temperature and time. The effect of the porosity and grain size on the hardness of the specimens was explained based on the modified plasticity theory of porous material and the Hall-Petch type equation. (c) 2007 Elsevier B.V. All rights reserved.