The aim of this work was to study the effect of temperature and heating rate on the densification of two leucite-based dental porcelains: one low-fusion and one high-fusion commercial leucite porcelains (Dentsply-Ceramco). Porcelain powders were characterized by differential thermal analysis (DTA), X-ray diffraction (XRD), particle size distribution, and helium picnometry. Bar samples were sintered from 650 to 1050oC, using heating rate of 55oC and 10oC/min. Sintered samples were characterized in terms of bulk density, measured by the Archimedes method in water, and fractured surface microstructure by scanning electron microscopy (SEM). The results show that densification increases with increasing temperature and the increase in heating rate has no effect on the densification of the porcelains studied.