The sintering behavior and mechanical properties of WC-Co and WC-Ni hard materials produced by high-frequency induction-heating sintering (HFIHS) were compared using ultra fine WC, WC-Co, and WC-Ni powders. HFIHS allows very quick densification to near theoretical density and prohibits grain growth in nano-structured materials. Highly dense WC, WC-Co, and WC-Ni with a relative density of up to 99.2% could be obtained with simultaneous application of 60 MPa pressure and induced current within 2 min without significant change in grain size. The hardness and fracture toughness of the dense WC, WC-Co, and WC-Ni composites produced by HFIHS were also investigated.