Pressureless sintered SIC specimens were joined using MgO-Al2O3-SiO2 (MAS) filler. MAS filler showed excellent behaviour of wetting on SIC substrate above 1480 degrees C, and the wettability was much influenced by the joining atmosphere. The joining was carried out at 1500 and 1600 degrees C for 30 min in Ar atmosphere. The flexural strength of the joined specimen showed 342-380 MPa up to 800 degrees C. However, the flexural strength of the joined specimen decreased to about 80 MPa at 900 degrees C due to softening of the joint interlayer. The results of the XRD and WDS showed that the reaction between SIC and the MAS filler produced the oxycarbide glass.