The asymmetrical half-bridge converter is widely used for PC power supply. However, severe inrush current produces in this converter at start-up. This paper presents startup inrush current reduction technique of asymmetrical halfbridge DC/DC converter for PC power supply. The proposed asymmetrical half-bridge converter is composed of series connected two link capacitors, center-tapped transformer and blocking capacitor. The proposed converter can reduce the severe start-up inrush current by using the small blocking capacitor. The validity of this study is confirmed from the experimental results.