The kinetics of the dissolution of phosphate rock and the crystallization of calcium sulfates, which occurs at the end of the reaction, were investigated in sulfuric acid solutions. The samples used in experiments were obtained from Mazidagi, Mardin, Turkey. The effects of the particle size, solid-to-liquid ratio, gas flow rate, and reaction temperature on the dissolution process were determined. A mathematical model in the following form, including the effects of parameters was established to express the dissolution kinetics of phosphate ore: -ln(1 - X) = kt(m). The activation energy for the process was found to be 29.66 kJ(.)mol(-1).