Abstract. The ostracods of the Miocene Marada Formation from three wells in the east of the Sirt Basin are described. These indicate ages ranging from Aquitainian to Tortonian. Four biozones are recognised: Pokornyella deformis minor (=Aquitainian), Aurilla soummamensis (=Burdigalian), an interval zone of Mid Miocene age, and Ruggieria tetraptera tetraptera (=Tortonian). 55 species have been identified, 22 of which are known from other Mediterranean localities. Six new species are described: Actinocythereis sirtensis sp. nov, Bythocypris tripoliensis sp. nov, Cyprideis maradaensis sp. nov, Cytheridea joshensis sp. nov, Gammudi, Hermanites zaltanensis sp. nov, and Paijenborchellina keeni sp. nov, Gammudi.