From Autumn 2019 to Spring 2021, LAB University of Applied Sciences had surveyed the role of product design in circular economy of textiles and clothing in the Telaketju 2 -project. The Designer's Guideline for Circular Clothing Design summarizes these studies and aims to raise awareness of how large the impacts and possibilities of the design choices are in the clothing industry. Publication is meant to act as a work book for clothing designer, encouraging to add own notes, sketches and design paths to it with handwrite like typography and sketch like illustrations.