ABSTRACT The Plio-Pleistocene deposits exposed in the Kallithea Bay section on the eastern coast of Rhodes comprise an overall transgressive sequence ranging from brackish water sand and gravel at the base to deep-water marl at the top. Variations in the distribution of ostracods were investigated in 41 samples covering the entire section. The brackish water succession contains a poor fauna of six species dominated by Cyprideis torosa and Loxoconcha cf. phaseola. The marine assemblages, in contrast, are very diverse, and nearly 200 taxa have been identified. A Q-mode cluster analysis grouped the marine samples into three biofacies. Each biofacies occupies a distinct part of the section and the biofacies are clearly linked to lithology and depositional environment. An R-mode cluster analysis of 58 selected taxa produced three fauna clusters, which with considerable confidence could be related to specific biofacies. Biofacies I includes the coarse-grained deposits in the lower part of the section. It is associated with species of Xestoleberis, Aurila, Callistocythere and other shallow-water ostracods. Biofacies II occupies the central part of the section. It is associated with species that today live mainly on the middle and outer shelf, e.g., Acanthocythereis hystrix, Bosquetina tarentina, Parakrithe dactylomorpha, Phlyctocythere pellucida and Cytheropteron sulcatum. Biofacies III, which comprises the uppermost fine-grained beds of the section, is associated with deep-water species such as Bythocypris bosquetiana, Bythocypris obtusata, Argilloecia acuminata Bosquetina rhodiensis, Buntonia textilis, and Henryhowella hirta. According to the ostracods, during the early Pleistocene, the water depth at the Kallithea Bay section increased from a few meters to 350-500 m. The offshore ostracod associations of biofacies II and III are intermixed with a large number of shallow-water species belonging mainly to Xestoleberis, Aurila, and Semicytherura. The shallow-water species consist almost exclusively of juvenile specimens and they are probably allochthonous. A number of laminated beds in the upper part of the section are almost entirely without indigenous species.