Contribution to the knowledge of the Cladocera fauna (Crustacea: Branchiopoda) in the Cienaga Grande de Santa Marta, Colombia. 108 samples collected between March, and November 2009 from macrophytes and open waters of the east coast of Cienaga Grande de Santa Marta, adjacent to Sevilla river, Magdalena Department were analyzed. A greater number of individuals and species were found in macrophytes rather than in open water. This is the first report on the Cladocera from this region. In total 36 species were recorded; eight of them are new records to Colombian fauna (Guernella raphaelis, Ilyocryptus plumosus, Moina eugeniae, Kurzia polyspina, K. media, Oxyruella longicaudis and O. tenuicaudis). A brief description of all species and their geographical distribution is included.