This paper focuses on core loss reduction of a consequent-pole bearingless disk motor using a C-shaped stator core made of soft magnetic composites (SMC). The core loss of the previously built test machine was significantly high, because the C-core has a three-dimensional flux path; therefore, conventional laminated steel cannot be used. In this paper, the solid iron core is replaced by the SMC, and its effectiveness is experimentally demonstrated. The core loss with solid iron, when the bearingless motor is driven at 3000 r/min under no load condition, is 3.8 W, but that with the SMC core is reduced to only 0.6 W. The maximum efficiency with solid iron is 27%, but that with the SMC core is improved to 61%. It is experimentally verified that the SMC core is effective to reduce the core loss and improve the efficiency of the bearingless disk motor with C-shaped stator cores.