Fabrication of Si2N2O phase free, fully densified Si3N4/SiC nano-nano composite ceramics was done by combining a carbothermal reduction treatment (CRT) and a spark plasma sintering (SPS) using commercially available Si3N4 and SiC nano-powders, and their mechanical and tribological properties were investigated. CRT was conducted at 1450 degrees C for 10 h with a phenolic resin and SPS was carried out at 1550 degrees C for 5 min, which yielded the fully dense (>98% of theoretical density) Si3N4/SiC nano-nano ceramics with similar to 100 nm grain size. The elastic modulus, hardness, and fracture toughness increased with increasing SiC content up to 20 wt%. The wear rate of Si3N4/SiC nano-nano ceramics decreased from 2.0x10(-5) to 6.76x10(-6) mm(3)/Nm with 20 wt% SiC addition, resulting from the increased hardness and fracture toughness.