In this work the changes in compressive strength and phase composition in respect of aging time of alpha-tricalcium phosphate (α-TCP) cements are examined. The increase of compressiove strength is time and initial pH dependent. Increase of aging time and initial pH leads to the increase of mechanical properties. A compressive strength up to 15 MPa was reached for cements with powder/liquid ratio 1.75g/1ml and initial liquid phase pH 8. More rapid conversion of α-TCP to hydroxyapatite occours at higher liquid phase pH values. The lower compressive strength of cements with acidic initial liquid phase pH can be explained by slower conversion of α-TCP and higher porosity after setting. The best setting and mechanical properties was achieved for cements with basic initial pH (8).