An efficient rhodium(III)‐catalyzed N−H insertion reaction is developed from the reaction of phosphoryl amides with α‐aryl diazoesters under aerobic and mild conditions, which produce α‐phosphoryl amino esters in good to excellent yields with high selectivity, a broad substrate scope, and a good functional group tolerance. Also, Rh(III)‐catalyzed N−H insertion reaction of alkenyl phosphonic amides with α‐aryl diazoesters was successful.