The experimental results concerning kinetic aspects of struvite precipitation in a continuous DTM-type crystallizer with internal circulation of suspension forced by a liquid jet-pump are presented and discussed. Nucleation and crystal growth rates of struvite during reaction-crystallization processes in diluted water solutions of magnesium, ammonium, and phosphate ions were identified. Kinetic parameters were calculated. on the basis of population density distributions adopting a simplified model of the mass crystallization process in a MSMPR crystallizer taking under consideration size-dependent growth (SDG) mechanism. The Rojkowski hyperbolic SDG model has proved to be the equation best statistically fitted to our own data set.