Recently, for the aspects of ecology and economy, fuel efficiency improvement demand has been increased globally. And, various types of hybrid systems have been suggested.In response to this market demand, AISIN SEIKI has been developing Synchronizer-less hybrid automated manual transmission (HV-AMT) system aiming excellent transmission efficiency, excellent agility, and shift change quality like a step automatic transmission (AT).This hybrid system is constructed based upon a parallel 2-axis manual transmission (MT) which originally has high transmission efficiency. The synchronizer system of a MT is replaced by a Dog clutch system which does not spoil the transmission efficiency and never makes failure in synchronization. This Dog clutch system includes a modified detent function, a shift actuator of linear motor, advanced function controls for a clutch and a shift actuator. The system does have a motor, the traction motor, perhaps say that it does not need an additional motor for synchronization.This hybrid system also realizes smooth acceleration feel of the vehicle like a step AT and excellent drive feel of a MT for agility and drivability, eliminating torque interruption at power-on-down shift or power-on-up shift by coordinate control of a hybrid motor generator (MG), a clutch and an engine.In this paper, AISIN SEIKI describes the “Synchronizer-less system” for the HV-AMT system.