A copper-catalyzed P–H insertion reaction between sulfoxonium ylides and H-phosphorus oxides has been demonstrated, furnishing α-phosphonyl carboxylate derivatives in 41–93% yields. This methodology utilizing bench-stable and thermodynamically stable sulfoxonium ylides as carbene precursors in the presence of the inexpensive and readily available copper catalyst shows advantages such as mild reaction conditions, good functional group compatibility, and easy scale-up, which make this protocol attractive for large-scale chemical processing and processing at the industrial scale.