Development of the harpacticoid copepod Euterpina acutifrons at four temperatures (12, 15, 18 and 21 C) was studied in the laboratory using cultured individuals originating from the Gulf of Marseille (France). The animals were fed on a monospecific culture of Phaeodactylum tricornutum throughout the whole life cycle. Development duration is negatively correlated with temperature and can be described by Belehradek's equation (1935). The influence of temperature on duration of the various stages (embryonic, larval and postlarval) is not constant. A more rapid development of small males was noted at all temperatures.