The dry weights, carbon and nitrogen content of fresh dried Calanus spp. Pseudocalanus elongatus, Acartia clausi, Temora longicornis, Mesocalanus teniricornis, Metridia lucens and Candacia armata were determined from samples taken in the southern North Sea, the English Channel, the Irish Sea and the Celtic Sea in December 1984 and February 1987. Usually adult females were picked out but some data were obtained for adult males and copepodites of Calanus spp. and T. longicornis and male M. tenuicornis. Significant differences were found between stations on the same cruise in the results for adult females of the same species. The weights of Calanus spp. females in February 1987 were found to be inversely related to temperature.