Investigations of supermolecular structure and tensile properties of colored heat-stabilized fibers were carried out. For fiber coloring, chosen organic pigments with differentiated nucleating properties were used. It was stated that during the fiber formation, a fibrillar-lamellar structure with alpha-crystals is formed. In fibers colored with a quinacridone pigment, the minimal number of beta-crystals was observed. During heat-stabilization, perfecting of the supermolecular structure of the fiber occurs. Because of pigments, the process of rebuilding occurs more intensively and leads to formation of a more stable structure with higher crystallinity.