The aim of this paper is to present the basic concepts of advanced high strength steels (AHSS) for use in the automobile industry, including chemical composition design, microstructure and mechanical properties development during thermomechanical processing, production technology characterisation, potential applications and performance in service. AHSS steels are considered to be the major materials for future applications in this production sector. As opposed to the cold formable single phase deep-drawable grades, the mechanical properties of AHSS steels are controlled by many factors, including: phase composition and distribution in the overall microstructure, volume fraction, size and morphology of phase constituents, as well as stability of metastable constituents. The main feature of these steels is that they do not permit to rely on the well-established traditional microstructure-properties relationships. Therefore, many different alloy concepts and alternative processing routes are still under development by different steel producers for comparable steel grades.