The use of a new generation chemical fibers with various functional additives offers new possibilities for the development of advanced (multi)functional textile products. Such compounds as phase change materials (PCMs), metals (like cooper, silver), also natural or chemical insect repellents, FIR emitting ceramic particles and etc. incorporated into fibres’ structure are essential for development of knitted fabrics directly contacting to the skin with effective thermoregulation and such protective properties as: antimicrobial, antistatic, repellence against blood sucking insects. The main parts of socks investigated were knitted in plain plated single jersey pattern. The 3-ply twisted yarns of new structures were used in the outer layer of socks. Yarns were made by using single yarns with PCMs, insect repellent permethrin, ceramic and silver additives containing fibres (Cell Solution® Clima, Cell Solution® Protection, Resistex® Silver). The inner layer of socks was made of polyester (PES) 3-ply twisted yarns with different number of filaments resulted in different structures of socks’ fabric. Based on all obtained thermoregulating and protective characteristics of investigated different knitted fabric structures of socks, the optimal knitted socks were selected. The obtained results of investigations are significant for the development of other knitted fabrics worn next to the skin.