Bioethanol is nowadays one of the main actors in the fuel market. It is currently produced from sugars and starchy materials, but lignocelluloses expect to be major feedstocks for ethanol production in the future. Two processes are developed in parallel for utilization of lignocelluloses to ethanol, “acid-based” and “enzyme-based” processes. The current article is dedicated to review the progress of “acid-based-hydrolysis” process. This process was industrially used in 1940s, during wartime, but was not economically competitive afterward. However, intensive research and development on its technology in the last three decades and expanding ethanol market may revive the process in large scale once again. In this paper, ethanol market, composition of lignocellulosic materials, concentrated- and dilute-acid pretreatment and hydrolysis, plug-flow, percolation, counter-current and shrinking-bed hydrolysis reactors, fermentation of hexoses and pentoses, effects of fermentation inhibitors, downstream processing, wastewater treatment, analytical methods used, and the current commercial status of the acid-based ethanol processes is reviewed.