The binary phase diagram of the mandelic acid enantiomers and the binary and ternary phase diagrams of the same enantiomer(s) and water are studied as a typical enantiomeric system. The results of the experimental work performed are presented in detail and discussed both with regard to the applicability of different methods for solubility measurement and their importance for crystallization based enantioseparation. It will be shown that, in addition to classical methods differential scanning calorimetry (DSC) can be applied successfully for solubility determination. From the obtained phase diagram various possibilities of gaining pure mandelic acid enantiomers from aqueous solutions are derived. The particular role of the eutectic composition in the enantiomeric system is emphasized.