The main purpose of the present contribution is the study of the glassy state and the presence of crystals in hard Isomalt candies. Crystallization in the glassy state of hard candies occurs as a result of the bad formulation, processing or storage and can be detrimental to the product quality. Samples were measured two weeks after the date of production and then after storage in a closed space with relative humidity 65 %. Differential scanning calorimetry was used to determine the glass transition temperature Tg and the amount of crystals. Polarisation microscopy and X-ray diffractometry were used to show the undesirable presence of crystals. The saccharide composition of samples was determined by HPLC and the water content by the Karl Fischer method. Water absorption after storage was determined by weighing.