Catalytically active molybdenum oxycarbide has been successfully prepared on an efficient carrier, SiC. Comparisons with the conventional alumina support show that the strong interaction between MoO3, the starting material, and Al2O3, partially blocks the formation of the oxycarbide; the active phase can only be prepared at very high loading. X-ray diffraction and temperature-programmed reduction are used to follow the different types of interaction between the precursor, the carrier and the active phase. Isomerization tests of n-C-6 and n-C-7 at various pressures confirm that the SiC supported catalyst does not lose its very interesting properties in terms of selectivity versus activity previously found for the bulk materials.