Densification behavior, microstructural developments and mechanical properties of 5 wt% SiC nano particulate toughened Al2O3 composites were prepared by using microwave sintering at different sintering temperatures. Densities of up to 97.5% of the theoretical value were achieved at temperature as low as 1380°C. Improvements in fracture toughness and bending strengths are of the order of 99% theoretical dense conventionally sintered composites. Surface heating was observed at the final stages of densification. No thermal runaway was observed in the nanocomposites due to presence of SiC spheroids.