This chapter provides an up-to-date overview of fermentative hydrogen production from organic solid wastes. Numerous recent works have reported that abundant organic solid wastes from households, agriculture, and industry are potential feedstocks for hydrogen production, which can be exploited for waste management and energy production at the same time. However, the hydrogen production potential varies widely depending on the substrate components. This chapter thus deals with the characteristics of various organic solid wastes. Several effective strategies, including hydrolysis and sterilization methods to render organic solid wastes as a feasible substrate for effective hydrogen production, are presented. Hydrogen production is not only restricted by the composition of organic wastes, but also is dependent on the operational conditions. Thus, key parameters affecting hydrogen production, such as pH, temperature, nutrient supplementation, and hydraulic retention time, are reviewed. In addition, reactor types suitable for enhancing hydrogen production are also discussed.