The phytoplanktonic community structure of the restored Juan Amarillo wetland was studied from 2003 to 2007. Dynamics of the first successional stages revealed dominance by chlorophycean algae followed by an alternation of cyanobacterial blooms, which began with Anabaena fol-Iowed by Microcystis-like species. A permanent bloom of Woronichinia cf fosca occurred in 2006. The objective of our study was to analyze the main physical and chemical factors that may have Ied to the occurrence of these prolonged cyanobacterial