The photolytic production of hydrogen from water by photoelectrochemical and photobiological approaches has the potential for efficient and low-cost generation of hydrogen. Both of these approaches have been sporadically studied for decades, but only in recent years have major advances been made in materials and device technologies that make these options viable alternatives to many pathways to the generation of hydrogen. The successful integration of high- efficiency multijunction photovoltaic devices in a photoelectrochemical configuration has led to a significant increase in hydrogen generation efficiency. As new ideas on ultra-high efficiency and low-cost PV materials and devices are pursued, they will undoubtedly have a synergistic effect on advancing the photoelectrochemical approaches to generation of hydrogen. Similarly, recent progress in genetic engineering of micro algae capable of producing hydrogen by photosynthetic processes has led to a more efficient and sustained generation of hydrogen with great potential for a future hydrogen economy. A brief overview of these two technologies with particular emphasis on NREL’s research activities in these areas will be given in this presentation.