The chemical composition of Kevlar aramid fiber is poly para-phenyleneterephthalamide. Para-aramid fibers belong to a class of materials known as liquid crystalline polymers. This article discusses the manufacture of aramid fibers and the major fiber forms, such as continuous filament yarns, rovings, woven fabrics, discontinuous staple and spun yarns, fabrics, and pulp. Key representative properties of para-aramid fibers are listed in a table. The article reviews the properties of aramid fibers, including tensile modulus, tensile strength, creep and fatigue, compressive properties, toughness, thermal properties, as well as electrical and optical properties. It concludes with a discussion on the environmental behavior of para-aramid fibers.