The study presents an investigation of thermoregulatory processes of ceramic-containing textile materials used in cold environments. Bio-ceramic additives have a heat-retaining function caused by its far-infrared (FIR) radiation. Storing heat at a high temperature, bioceramics can radiate heat to the body when the temperature outside drops. In order to improve the thermal efficiency of fabrics primarily worn next to the skin, our intention was to increase the active surface area of the ceramic-containing textile material. For this purpose a combined knitted PET fibre textile material was used, which was treated with ceramic additives using different application methods. Tests were performed where specimens were kept in a constant temperature oven, then placed on a cold surface, and the temperature decrease of the specimens was periodically recorded in a given time period. The results revealed that the highest heat accumulation was determined in screen-printed fabric with continuous coating, and the lowest – in PET fabric knitted of bio-ceramic containing fibres. Key words: thermal insulation, bio-ceramics, far infrared radiation, thermal comfort.