The friction and wear properties of oil-retaining porous silicon carbide and dense silicon carbide in air were studied by using a pin-on-disk friction machine. The tribological properties and morphologies of the worn surfaces of these ceramics were greatly changed depending on the test conditions such as loads applied and the combinations of materials (pin/disk). Dense SiC pin showed a lower and more stable friction coefficient and less wear than those of self-mated dense SiC, when it was slid against the oil-retaining porous SiC disk. The friction and wear mechanisms of these ceramics were discussed from the tribological properties obtained and the morphologies of the worn surfaces by SEM and three-dimensional surface roughness observation.