Nanostructured WC-Co coatings have been manufactured by high velocity oxyfuel (HVOF) spraying using commercially available nanocomposite powders. The effect of feedstock powder characteristics on coating microstructure has been investigated. A significant loss of carbon occurred during HVOF spraying, which was much greater for a porous, irregular powder than for a dense, spherical powder. The decarburization promoted the formation of several additional phases in the coating, including W2C, W and CoxWxC. The microstructural differences in each coating arose from the different extent of feedstock powder melting because of initial powder morphology.