(Si-Al-O-N) (sialon)-SiC whisker (SiCw) composites containing up to 10 mass% SiCw were prepared by hot isostatic pressing. The strengths and the fracture toughness of composites remained relatively unchanged with the amount of SiCw. The addition of SiCw enabled us to improve the creep properties of sialon ceramics. The total creep strain and steady-state creep rate at 1473 K under a stress of 400-500 MPa decreased with increasing the amount of SiCw. The experimental creep exponent values of monolithic sialon and sialon-SiCw composites were nearly 1. It is supposed that the creep of both monolithic sialon and sialon-SiCw composites are dominated by the viscous flow of the interglanular glassy phase.