Abstract: On the southeastern coast of the Greek island of Rhodes, late Pliocene and early Pleistocene marine deposits are dominated by bryozoans. In the studied section, one of the Pliocene calcareous clay beds contains densely packed nodular arborescent colonies of the celleporid species Celleporaria palmata. They form thickets approximately 0.8 m in height and are associated with numerous remains of other organisms, among them mostly encrusting but also erect bryozoans. From the indications given by known depth ranges of extant bryozoan species, associated zoarial forms and ecology of living celleporids, a reconstruction of the paleoenvironment is attempted. A depth of about 30-50 m is suggested for the celleporid thickets. Comparison with analogous cool-water bryozoan deposits, both Recent and fossil, especially from Australia, shows that in spite of differences in depositional depth, energy and temperature, the bryozoan-dominated marine sediments of Rhodes possess the environmental and facies attributes typical of non-tropical shelf carbonates.