Short-channel effects in SiC MOSFETs have been investigated. Planar MOSFETs with various channel lengths have been fabricated on p-type 4H-SiC (0001), (000-1) and (11-20) faces.^Short-channel effects such as punchthrough behavior, decrease of threshold voltage and deterioration of subthreshold characteristics are observed. Furthermore, the critical channel lengths below which short-channel effects occur are analyzed as a function of p-body doping and oxide thickness by using device simulation. The critical channel lengths in the fabricated SiC MOSFETs are in agreement with those obtained from the device simulation. The results are also in agreement with the empirical relationship for Si MOSFETs.