The huge global energy consumption has raised concerns over the depletion in readily available conventional energy resources. Besides, there are harmful atmospheric effects of fossil fuels and the qualms of future energy resources. The world hence is in dire need of new renewable energy sources that are cheap, non-polluting, environmentally friendly, and clean. This is the only way we can stop using fossil. Hydrogen is considered as an ideal fuel for the future because of its high energy content and its clean combustion to water. However, extensive technologies are required to introduce hydrogen as an alternative clean and cost-effective future fuel, which brings about the relevance of the exploitation of the microorganisms for large-scale renewable energy production. Reports of photobiological hydrogen production by oxygenic photosynthetic microbes, such as green algae and cyanobacteria and by anaerobic photosynthesis, are summarized in this paper, with a focus on the major obstacles that must be overcome by scientific and technical breakthroughs to make way for commercially feasible energy. The principle, progress, and prognosis of photobiological hydrogen as a renewable energy source are reviewed.