Nanostructured materials and nanocomposites have the potential to have a dramatic impact on technological progress in the 21st century. Of great interest, is the outstanding deformation behavior of nanostructured materials and nanocomposites. In this study, the fatigue and mechanical properties of HVOF sprayed nanostructured and conventional WC-Co coatings were investigated. High velocity oxy-fuel process was used to spray the WC-12Co from a feedstock in which the WC phase was mainly in the micron size range (conventional) or contains a significant fraction of nanosized grains (multimodal).The fatigue strength of coatings deposited onto Aluminum alloy showed that the nanostructured WC-Co coated specimens exhibited higher fatigue strength compared to the conventional WC-Co coatings. Microhardness test was performed. Relationships between the microstructures and mechanical properties were discussed.