As the energy demand is continuously rising with the increase in population, the use of fossil fuels is also increasing at the same rate. These fossil fuels release greenhouse gases (GHG) which are harmful to human health and our environmental health and these fuels are also expected to exhaust in the near future. This eventually has led to an emerging need to shift to a more reliable, sustainable, clean energy source. Biohydrogen as fuel is a potential alternative, as hydrogen has proved to be one such fuel which has the potential to replace fossil fuels. There is a need to produce it in a clean, sustainable way to compete with the fuels that are being used currently. The hydrogen which is produced biologically is known as biohydrogen. Microorganisms also play a huge role in the process of hydrogen generation by virtue of their natural mechanism. Hydrogen can be produced biologically using approaches like biophotolysis (direct and indirect), fermentation (dark and photo) and microbial electrolysis cell (MEC). Among all, dark fermentation seems to be the most efficient when compared to other procedures. The challenges currently being faced with this technology are the yield of hydrogen, the high cost of the reactor and system efficiency. This technology still needs a lot of research and improvement to replace fossil fuels entirely.