Alkali fusion after acid digestion method (AFAD) was used for determination by ICP-MS of twenty-five trace elements (Rb, Sr, Y, Zr, Nb, Cs, Ba, Hf, Pb, Th, U, and rare earth elements) in four silicate reference materials (JG-1a, JG-2, and JG-3 granitoids and JB-2 basalt) from the Geological Survey of Japan (GSJ). Results were compared with those obtained by acid digestion (AD) method. Our results are in excellent agreement with previously reported data obtained by fusion methods. The reproducibility of replicate analyses is better than 5% (1σ) for all the elements, except Rb, Cs, and Pb in JG-2.