Volumetric characteristics of high-entropy alloys (HEAs) are among the main ones when considering possible practical applications of these materials. Low specific gravity is an important parameter providing the use of these alloys in industry. Density of AlNiCoCuZr HEAs with different component ratios has been experimentally investigated in the present work in a wide temperature range, including liquid state. Molar volume in liquid state and temperature coefficients of expansion in full temperature range (from room temperature up to 1800 K) were calculated basing on the experimental data. Structure of the alloys and thermal reactions during heating and cooling were studied. Two BCC - solid solutions, as well as solution based on (half)-Heusler phase ZrNi2Al were found. The presented results can provide a basis for further experimental study of AlNiCoCuZr HEAs and numerical modeling of their properties. © 2024 Elsevier Ltd.