An updated state-of-the-art review has been made of the new-generation high-strength low-alloy steels known as the acicular ferrite Mn-Mo-Nb steels. After individual effects of the various alloying elements were reviewed from the results of earlier research and published data, the importance of processing variables in commercial production was stressed. The most important benefits that can be realized pertain to the upgrading of impact toughness properties by the use of: 1) lower slab reheating temperatures, e.g., 1080–1150°C, 2) large total reductions, e.g., 65% below 900°C, and 3) low finish-rolling temperatures, e.g., 740–780°C. The strength properties are relatively insensitive to variations in hot-rolling schedules because there is a good balance of the three main strengthening mechanisms: grain refinement, dislocation substructure, and precipitation strengthening by Nb(C, N).