Direct electrocarboxylation of various N-acylimines with atmospheric CO2 is achieved in an undivided cell under mild conditions, affording substituted α-amino acids in yields of 62-95%. This reaction is conducted with high efficiency using triethanolamine as an external reductant under nonsacrificial anode conditions, and can be facilely performed on gram scale. Preliminary mechanistic studies including cyclic voltammetry and control experiments support N-radical carbanion as the key intermediate.