The IV International Rhodolith Workshop, held in Granada (Spain) in 2012, was the continuation of a series of meetings that started with the first workshop at Cumbrae Isle (Scotland, United Kingdom) in 2000. After that scientific event, the second rhodolith workshop took place in La Paz (Baja California Sur, Mexico) in 2006 and, the third in Búzios (Brazil) in 2009. The IV International Rhodolith Workshop of Granada was organized by Julio Aguirre, Juan C. Braga and Anja Rösler (Universidad de Granada).