The present work was performed to improve the mechanical strength of porous calcium phosphate blocks by adding a little amount of montmorillonite mineral to the calcium phosphate composition. 3.5 wt % of the montmorillonite mineral was added to the slurry of precipitated hydroxyapatite and the porosity was produced by infiltration of a polymer template. After the firing process (1200 oC), the compressive strength, phase composition, morphology and dissolution behavior of the porous bodies were evaluated by appropriate techniques. It was found that the additive improved the mechanical strength but decreased the dissolution rate of the porous calcium phosphate body. Also the final composition of the porous block (i.e. hydroxyapatite, HA, and β- tricalcium phosphate, β-TCP) was not influenced through the presence of the additive. It is suggested that the montmorillonite mineral can improve the sintering performance of the HA and β- TCP.