Following our recent successful fabrication of bulk cementite (Fe,C, 0) by mechanical alloying (MA) and subsequent spark plasma sintering (SPS), the influence of Cr, Mn, V, Mo, Ti, Ni and Si additions on the structure and properties of cementite bulk has been studied. It has been found that Cr, Mn, V and Mo can form alloyed cementite containing more than 5% of the alloying element and stabilize it, while Ti, Ni and Si destabilize or even completely suppress the formation of cementite. The hardness and Young's modulus of the alloyed cementite were increased in the order of V, Cr, Mn and Mo. The contribution of alloying elements to the hardness and Young's modulus was found to correlate well with their enhancement of bonding strength with iron atoms. At higher temperature, the alloyed cementite showed a higher hardness and compression strength. The large effect of Mo and V can be explained by misfit parameter of atomic radii. Thermal expansion coefficient of all the cementite shows an abnormally low value just below Curie temperature due to magnetostriction.