The family of commercially produced high-strength, high-modulus fibres and yarns for the manufacture of technical textiles and construction composites, based on aromatic para-polyamides-poly-para-phenyiene-terephphtalamide (Kevlar, Twaron), copolymers (Terlon, Technora), poly-para-hereroarylenes (SVM, Armos), was discussed and compared in the paper. The necessity of drawing such a comparison resulted from the fact that although there were papers on individual para-aramide fibres, but no comparative analysis of their structure and properties was performed yet. Therefore the main para-aramide fibres, their structure and its optimisation, their properties and ways of controlling these properties were reviewed in the paper. While discussing the main features of para-aramide fibres the following indices were taken into account: optimal molecular polarity and rigidity, energy of interatomic and intermolecular interactions. 3-D regularity, axial orientation, equal length of molecular chains in amorphous regions, etc. A special attention was paid to Armos (R) fibres manufactured by J.S. "Tverkhimvolokno" Company because they have several advantages over other para-aramide fibres as concerns mechanical and thermal properties. Currently J.-S, "Tverkhimvolokno" Company manufactures Armos (R) yarns and roving with tenacity higher than 4.5 - 5.0 GPa and elasticity modulus over 145 GPa.