Different quantities of additives (sodium chloride and oxalic acid) and antisolvent (ethanol) were used in order to define their influence on crystallization of glycine from aqueous solutions. The solubility curves were determined for all process conditions but the nucleation points only for the initial concentration of glycine. The obtained results showed that both the quantity and type of the additive affect the solubility curves, the metastable zone width as well as the granulometric characteristics of crystals (aspect ratio, external shape, and the crystal size distribution). X-ray analysis confirmed occurrences of gamma-glycine by adding sodium chloride and oxalic acid, regardless of the added mass while the alpha-polymorphs were achieved by adding ethanol.