Abstract In present paper we investigated the influence of Al2O3 nanoparticles on the specific heat capacity of isopropyl alcohol in the temperature range 80–186 K. The measurements of the specific heat capacity were performed by an adiabatic calorimeter. It was found that below the melting temperatures the solution of isopropyl alcohol with Al2O3 nanoparticles can be in crystalline, glassy and liquid metastable states. The presence of Al2O3 nanoparticles in isopropyl alcohol leads to a decrease of the specific heat capacity and the enthalpy of phase transitions “crystalline state – liquid” and “glassy state – liquid metastable state”. It was demonstrated that not only presence of the nanoparticles but also the existence of the adsorbed interfacial phase from the molecules of the base liquid around the nanoparticles decreases the isopropyl alcohol melting heat. Based on obtained experimental data for the melting heat of the nanofluids of isopropyl alcohol/Al2O3 the mass fraction of the base fluid in the interfacial phase and the mean equivalent radius of nanoparticles with interfacial phase have been determined at the melting point.