Investigations on the effect of the bentonite (B), fly ash (FA) and silica fume (SF) on the bleeding of cement-based grouts were reported here. Three additives (B, FA and SF) were used in the grout mixes to improve the bleeding of the grouts. Taguchi method was applied for the experiments and standard L-16 orthogonal array (OA) with three factors and four levels were chosen. In the preparation of the cement grouts, B, FA and SF were used at the ratios of 0-0.5-1-3%, 10-20-30-40% and 0-5-10-20%, respectively. The experiments were performed for three water/solid (W/S) ratios. Experimental results showed that the most effective material for the bleeding is SF. The bleeding decreased with the increase in SF and B ratio, while there was no noticeable difference with the increase of FA. Optimum conditions for minimum bleeding were obtained at 3% B, 10% FA and 20% SF for both grouts with W/S ratios of 0.75 and 1.0, while they were obtained 3% B, 20% FA and 20% SF for WIS ratio of 1.25. The Taguchi method was found to be promising tool to obtain the optimum conditions for such studies. (C) 2004 Elsevier Ltd. All rights reserved.