Nanoparticles as drug carriers can provide targeted/localized delivery and controlled drug release, but also encounter limitations due to physical and chemical instability. To improve the stability of suspension of nanoparticles, drying procedures are carried out. Freeze-drying is one of the most efficient methods of colloidal system drying. The process of freeze-drying of colloidal drug delivery system needs to be optimized in order to protect nanoparticles from stress generated during freezing and drying steps. For this purpose, different cryo/lyoprotectants are used. The aim of this work was to investigate the cryo/lyoprotective effect of glucose and trehalose (1-10 %, w/V) during freeze-drying of dexamethasone-loaded lipid/alginate nanoparticles suspension. In order to evaluate the effectiveness of selected cryo/lyoprotectants, nanoparticles were characterised in terms of size, polydispersity and zeta-potential before and after the freeze-drying. Dexamethasone-loaded lipid/alginate nanoparticles were prepared by ionic interaction of lipid (lecithin and cationic lipid) mixture and alginate. Nanoparticles were prepared using two different types of lecithin (lecithin S45 or lecithin S100) and at different cationic lipid-to-lecithin weight ratios (from 0,7:50 to 9:50). Size of nanoparticles remained preserved after freeze-drying in the presence of trehalose at the concentration of 10% (w/V), for both lecithin types and all cationic lipid-to-lecithin weight ratios used. In the presence of glucose, nanoparticles size remained preserved only in the case of freeze-drying of nanoparticles prepared with lecithin S45 at cationic lipid-to-lecithin weight ratio of 7:50, and glucose at the concentration of 5 and 10% (w/V). The best preservation of zeta-potential of nanoparticles was achieved in the case of freeze-drying of nanoparticles prepared with lecithin S45 and with the addition of trehalose as a cryo/lioprotectant. Freeze-drying of suspension of nanoparticles in the presence of trehalose as a cryo/lioprotectant resulted in lyophilisate which occupied a volume equal to the volume of the suspension prior to freeze-drying. In the case of freeze-drying in the presence of glucose as a cryo/lioprotectant, collapse of the lyophilisate structure was observed. Conducted preliminary studies suggested that trehalose was better cryo/lyoprotectant than glucose in the freeze-drying process of dexamethasone-loaded lipid/alginate nanoparticles.