In this paper, we describe the ac resistance of a coil using a magnetoplated wire (MPW), which is prepared by circumferentially plating a copper wire with magnetic thin film. The Q value of the MPW coil is higher than that of a coil using a copper wire without magnetic thin film plating (COW coil). High-Q coils have lower loss and are required in various industrial fields. To further improve the Q-value characteristics of the MPW coil, it is necessary to theoretically analyze its ac resistance. We theoretically analyzed the ac resistance of coils generated by skin and proximity effects. The measured and calculated ac resistances of the MPW coil were in good agreement with a difference of 4%. In addition, the ac resistance generated by the proximity effect was reduced in the MPW coil, and was 50% of that in the COW coil.