Biomass can also be used as a substrate for energy production, particularly for hydrogen production. By use of microorganisms, hydrogen can effectively be obtained from wood and marine biomass according to purposes. Biomass (i.e., organic matter) such as marine macro algae can be degraded biologically. The use of seaweeds as energy crops have certain advantages: the need for large land areas (which may not be available) is avoided; marine crop yields are expected to be considerably higher than land crop yields although experience from large-scale cultivation is lacking; seaweeds do not contain lignin, which is almost non-degradable under anaerobic conditions; and many valuable extracts, such as alginate, can be extracted from the waste, which is important to environmental protection. Recent research has shown that the red algae Gelidium amansii and the brown algae Laminaria japonica are both potential biomass sources for biohydrogen production through anaerobic fermentation. The objective of this review article is to give an overview of marine algae as a prospective source for biohydrogen production. © Springer Science+Business Media Dordrecht 2013.