In recent years, there has been a significant effort among researchers to develop calcium orthophosphate based biomaterials and biomedical devices for prosthetic applications and dental implants. Although the properties of these calcium orthophosphates are quite well-known, very little information is available on the growth and nucleation kinetics of these substances. In the present study, the reactive crystallization of calcium phosphate was studied in a batch system at 25 degreesC. The initial calcium and phosphorus concentration in the reactor was varied from 0.01 to 0.04 mol/dm(3), and the solution pH was kept under 6. Analysis by XRD, FTIR, atomic absorption and UV spectroscopy revealed that the crystals precipitated from the solution were pure brushite (dicalcium phosphate dihydrate). From the experimental determination of crystal size distribution, and with the aid of a rigorous mathematical model of the process in conjunction with a nonlinear optimization program, nucleation and two-dimensional growth kinetics of brushite crystals were determined. The existence of the two-dimensional growth rate was supported by the plate shape morphology of the growing crystals studied by scanning electron microscopy (SEM).