Pulsed blue light at 489nm has been generated by second-harmonic-generation of a nanosecond pulsed master oscillator power amplifier system based on a short Yb3+ doped single-mode fiber amplifier at 978nm and an external-cavity diode laser as seed source. The Yb3+-doped fiber was core-pumped by a W type Nd3+ doped doubleclad fiber laser operating on the transition near 930nm (4F3/2 ? 4I9/2). 520mW of average power was generated at 489nm using a periodically poled MgO:LiNbO3, corresponding to a conversion efficiency of 34%.