We have evaluated the electronic stopping power, dE/dx, for channeled antiprotons which perform helical motion along an axis of Si(110) for an energy region from a few hundred keV to a few MeV. The conclusive factors to discuss the channeled fraction and dE/dxare two; the energyEand the ratio of incident tilt angle to ψL, where ψLis Lindhard's critical angle for channeling of a proton. The channeled fraction shows a maximum around /ψL≈ 0.6. At the same time, a prominent energy loss is found for channeled antiprotons by more than a factor of six as is compared with random ones. This implies the dE/dxfor channeled antiprotons would be even higher than that for random protons.