A small Xe flashlamp-pumped Nd : MgO : LiNbO3 selffrequency- doubled laser at room temperature is described. The laser device could be operated with 400μJ/shot output of pure green light at 26°C. The threshold is smaller than 4.8 J. The optimum phase-matching could be achieved over 15°C to 45°C, if the crystal was aligned and no photorefractive damage was observed. © 1990, The Institution of Electrical Engineers. All rights reserved.