Abstract Mixtures of sugar alcohols xylitol, D-sorbitol and D-mannitol were prepared by grinding the solid starting materials together for 20 min. Possible co-crystals were identified by DSC and X-ray powder diffraction. The phase diagrams for the systems xylitol-D-sorbitol, xylitol-D-mannitol and D-sorbitol-D-mannitol were created using the peak values from the DSC measurements as melting points. The phase diagram for xylitol and D-sorbitol showed that co-crystallization between these two components may be achieved by grinding them together. The powder diffraction pattern for a mixture of 0.50 mole fraction of xylitol and 0.50 mole fraction of D-sorbitol showed that the product consisted of both starting reagents and a new co-crystallization product. The melting point of the co-crystallization product was 75–77°C measured from the peak value of DSC measurements.