<p>Synthetic hydroxyapatite is a biomaterial widely used for the production of medical ceramics and coatings, but its thermophysical properties have not been sufficiently studied. In this work, a comprehensive study of the thermal conductivity and the thermal diffusivity of ceramic samples sintered at different temperatures was carried out for the first time. The thermal diffusivity was measured over a wide temperature range (up to 1325&#xa0;K) using the laser flash method. The isobaric heat capacity of hydroxyapatite was studied using the method of differential scanning calorimetry. Based on the obtained experimental results, the thermal conductivity was calculated. It was shown that with increase in the sintering temperature of green body up to 1473 K, its density increases (from 1955 kg·m^–3 to 2844 kg·m^–3), which leads to an increase in thermal diffusivity (from 0.196 m²·s^–1 to 0.460 m²·s^–1) and thermal conductivity (from 0.281 W·(m·K)^–1 to 0.963 W·(m·K)^–1) for a material having a temperature close to room temperature (293 K). Measurements at high temperatures indicate that the thermal diffusivity and the thermal conductivity of hydroxyapatite depend not only on the material density and temperature, but also on the concentration of hydroxyl groups in the hydroxyapatite crystal lattice. Increasing the material density shifts the thermal diffusivity and the thermal conductivity curves to higher values. The complete absence of hydroxyl groups, which is characteristic of the oxyapatite state, significantly changes the shape of the curve. The investigation indicates the importance of taking into account the degree of hydroxylation of apatite as it changes thermal properties of the material, which is very important and can be crucial in the manufacture of ceramic products.</p>