A new two-quadrant (2Q) zero-current-transition (ZCT) converter with the capabilities of 2Q power flow and ZCT switching profile for DC motor drives is presented. It possesses the advantages that both the main and auxiliary switches can operate with zero-current switching (ZCS), reduced switching losses and stresses, minimum voltage and current stresses as well as minimum circulating energy during both the motoring and regenerating modes. It also offers simple circuit topology, minimum component count and low cost. This converter is particularly useful for DC traction systems in which both motoring and regenerative braking are desired to have high efficiency. The corresponding theoretical analysis and its high-efficiency performance are supported by both simulation and experimental results.