Origins of nonreproducibility of kinetic characteristics and crystallization product properties during repeated processes are reviewed. The distribution functions of repeated crystallizations based on the kinetic parameters are introduced. Four models of variability, caused by variation of supersaturation, impurity quantity,nucleation activity of crystallizer walls and alteration of suspension flow inside the crystallizer, are analyzed. An experimental study of ammonium perchlorate crystallization in water solution demonstrated the variability of crystal size distribution due to negligible changes in a well-stirred batch crystallizer.