In this contribution, we report the results of a study to probe into the combined effect of the sintering conditions and mullite (3Al(2)O(3)center dot 2SiO(2)) addition (upto 30 wt%), on the densification mechanism, phase assemblage, and microstructure development in calcium phosphate (CaP)-mullite composites. The experimental results reveal that close to 95% theoretical density can be achieved by sintering the compositions in the temperature range of 1300 degrees-1350 degrees C. Finer scale microstructural analysis using transmission electron microscopy reveals the presence of both beta- and alpha-TCP (Ca(3)(PO(4))(2)-tricalcium phosphate) and a crystalline residue of gehlenite at triple junctions. The shrinkage kinetics of the composites have been analyzed to qualitatively understand the sintering mechanisms. For the composites, solid-state sintering in the initial stage, followed by liquid-phase sintering at or near the sintering temperature are postulated to explain the effect of temperature and volume fraction of the second phase. Some important features of the liquid-phase sintering have been discussed using the CaO-Al(2)O(3)-SiO(2) ternary phase diagram. A comparison with the earlier published results reveals that a better combination of long-crack fracture toughness, compressive strength, and flexural strength can be obtained with the newly developed composites.