The ostracod fauna of the interglacial channel deposits at Little Oakley, Essex, is described from samples collected from four boreholes located at different sites across the palaeochannel. Minor differences between boreholes are explained principally by the contrasting depositional environments reflecting marginal and mid-channel facies. For the most part, the faunas indicate fully temperate conditions although there are suggestions of less temperate conditions earlier in the interglacial. The absence of brackish-water species indicates that the river was upstream of any tidal influence. No ostracod faunas are known from strictly comparable facies from the British Lower or Middle Pleistocene and this makes an age assessment difficult on the basis of ostracods alone. Significant elements include Candona tricicatricosa, Ilyocypris quinculminata, Sclerocypris clavata prisca and Paralimnocythere compressa, together with an Ilyocypris that appears to constitute an undescribed species. This is described, illustrated and formally named Ilyocypris papillata. The critical taxa, in the proportions seen here, are consistent with a Cromerian age although none is confined to this period.