This article focuses on the isothermal semi-continuous crystallization of glycine aqueous solution by adding an anti-solvent, ethanol. The effect of the ethanol concentration on solubility and the impact of the ethanol flow rate on the metastable zone width and on the size distribution of the crystals were investigated. The study showed that increasing the ethanol concentration in the medium decreases solubility for the studied temperatures and that increasing the ethanol flow rate causes a widening of the metastable zone without inducing any noticeable effect on the crystals' size distribution. In addition, nucleation kinetic models were determined for two temperatures (30 and 56 degrees C).