The dissolution rate of ulexite in citric acid solutions was determined and the effects of the process parameters were investigated in this study. Statistical design of the experiments and the analysis of variance were performed in order to determine the main effects and the interactions among the investigated factors. The effects of parameters such as the reaction temperature, citric acid concentration, solid/liquid ratio and the particle size on the dissolution of ulexite were determined in the conducted experiments. The ranges for the experimental parameters were as follows: leaching temperature, 40-80 degrees C; citric acid concentration, 0.1-0.4M; solid/liquid ratio, 5-20% (w/v); particle size, (-1.7+0.85)-(-0.212) mm. It was determined that the B(2)O(3) dissolution increased with an increase in the citric acid concentration and the leaching temperature, and with a decrease in the solid/liquid ratio and the particle size. A simple linear mathematical model has been developed in order to predict the amount of B(2)O(3) extraction from ulexite concentrate for other operating conditions that were not directly tested. The optimum conditions within the selected parameter ranges were determined as 80 degrees C for the leaching temperature, 5% (w/v) for the solid/liquid ratio, 0.4M for the citric acid concentration, -0.212 mm for the particle size and 15 min for the leaching time. Under the stated conditions, the B(2)O(3) dissolution from ulexite in citric acid solution was determined as 97.28%.