Abstract:Eight species of the dinoflagellate genus Prorocen trum collected in April-May every year during 1998-2000 from Daya Bay, Guangdong, China, are identified and described. They are P. sigmoides, P. micans, P. tries tinum, P. dentatum, P. minimum, P. balticum, P. mexicanum, and an unknown species. All of them can cause red tide except the unknown one. P. minimum and P. mexicanum are susp ected of being toxic.