An innovative gel-casting process was developed in order to obtain macro porous ceramics scaffolds of hydroxyapatite to be used in regenerative medicine for bone tissue reconstruction. Mechanical investigation was carried out on different formulations of dense hydroxyapatite samples in order to evaluate the effect of the gel casting process parameters on the density, the elastic modulus, the tensile and the compressive strength. The fracture critical stress intensity factor (KIC) was also evaluated by means of microhardness measurements. The correlations between KIC and tensile and compressive strength were examined taking into account the average and maximum size of porosity. The mechanical properties of macro and micro-porous HA are in agreement with the model of Gibson and Ashby.