The development of new technologies and materials have enabled the possibility of a successful dispersion of nanoparticles in solvents thus forming nanosuspensions as an excellent media for heat or matter transfer with better properties than pure solvents. The ability of nanosuspensions to improve the transport properties in processes of heat and matter transfer could contribute to the energy efficiency of industrial processes. The primary requirement for accomplishing this kind of improvements is the preparation of stabile nanofluids. In this study, the possibility of applying deep eutectic solvents – DES, which are lately very often used as a replacement to conventional solvents, as base fluids for preparing stabile nanosuspensions was being tested. The stability of nanofluids is consisted of the ability of the suspension to stay homogeneous for a long period of time apropos, that there is no agglomeration and sedimentation of nanoparticles. The aim of this study was to research the stability of nanosuspensions prepared by dispersing Al2O3 nanoparticles in three different eutectic solvents. The stability has been evaluated using the visual method, sedimentation method applied in the centrifuge, microscope and by measuring the size distribution of the nanoparticles. As an important property of nanosuspensions, the heat transfer has also been measured. Even though the results did not match the expected outcome, they have shown that the selection of the suitable eutectic solvent is crucial in preparing nanosuspensions and that considering the results of stability determination methods, Ma-Fru-Gly-30 is the most suitable eutectic solvent for getting the most stabile nanosuspensions.