The current trend towards experiencing and practicing outdoor activities requires using activewear clothing whose design favors comfort, particularly thermophysiological comfort. One of the solutions to achieve adequate levels of this comfort is the use of functional fabrics in clothing design. One of the relevant aspects of these projects is the research on the interaction between design and technology. The development of fabrics to provide clothing with pleasant thermophysiological comfort levels for the user in harsher climatic environments cannot detract from ergonomic comfort, which guarantees the necessary and natural movements of the human body. The research was developed within the scope of the TexBoost R&D Project to design functional composite fabrics tailored for activewear apparel. In the research work, three trilaminated fabrics were developed, always considering for the baselayer or the outerlayer a FITECOM wool blend woven fabric, or knits and woven fabrics from different origins and compositions. To reinforce the functional character or contemporary aesthetics, two functional membranes with distinct characteristics, previously chosen from a group of four membranes, were used for the midlayer. The results of laboratory tests constitute an excellent tool for designing functional fabrics for activewear clothing, optimizing the balance between thermophysiological comfort, sensorial and body movement comfort and fashionable aesthetic.