Hydrogen combustion creates only water vapor, making it one of the greenest and least polluting fuels. This characteristic spurred the concept of a hydrogen-based economy in energy, instead of traditional sources such as oil, gasoline, coal, natural gas, and nuclear energy. Recently, the demand for hydrogen as a renewable energy carrier has increased sharply. Traditional hydrogen production methods, including water electrolysis, hydrocarbon steam reforming, and auto-thermal processes, are well established but economically unfeasible due to their high energy requirements. Biological hydrogen production offers distinct advantages over conventional chemical methods, encompassing bio-photolysis of water by algae and the fermentation of organic materials through dark fermentation (DF) and photo-fermentation (PF) using bacteria. Despite their innovative potential, DF and PF face challenges associated with raw material costs. Employing advanced biotechnological approaches, hydrogen can be economically produced from carbohydrate-rich, nitrogen-deficient solid wastes, such as cellulose- and starch-containing agricultural by-products, food-industry residues, and specific wastewater streams such as cheese whey, olive mill effluents, and baker’s yeast waste. Utilizing these waste materials not only enables cost-effective hydrogen production but also addresses pressing waste management concerns. This chapter covers the production of bio-hydrogen from different low-value materials, focusing on recent developments, challenges, and comparative advantages in the field.