A checklist on benthic marine algae of the Yum Balam Reserve, Quintana Roo, México, is presented. All species are "new records" for the area because this is the first study for the locality, 122 taxa were identified, 55 are species of Rhodophyta, 44 Chlorophyta and nine Phaeophyta. Batophora oerstedii v. occidentalis, Halodictyon mirabile, Hypoglossum involvens and Polysiphonia ramentacea are new records for the Yucatán Península.