Changes in species composition, abundance and biomass of copepods were monitored weekly over the year 1998 in shelf waters of the northern Levantine Basin. A total of 192 copepod species belonging to 61 genera were identified during the course of this study. Thirty-six species are reported for the first time from the region, including three new species. Copepod abundance ranged from 215 individuals m(-3) in early March to 2220 individuals m(-3) in late March, whereas the biomass ranged from 4 mg m(-3) in mid-January to 22 mg m(-3) in mid-February. The copepod fauna was found to be most species-rich on 4 November (Margalef's Index d = 7.4) and least on 10 March (d = 3.3). The index was found low during spring and autumn with lowest levels obtained during the stratification period from September to October. The diversity was found to be highest on 18 February (Shannon-Wiener Index H' = 2.9) and lowest on 31 March (H' = 1.6). Higher index values were characteristic of the winter period. A proportional representation of the species among their populations was well established during February whereas the best situation was met on 3 March and the most unbalanced situation at the end of March. Multivariate analyses have shown the formation of distinct seasonal communities of copepod species throughout the year. The observed seasonality in community structure is suggested to be a result of wide range changes in temperature throughout the year. The dominant species observed during late winter and spring were Oithona nana, Oithona sp., Oncaea media, Oncaea sp., Calocalanus elegans, Euterpina acutifrons and Oncaea zernovi, respectively. Calocalanus sp., C. elegans, Triconia dentipes, Oncaea sp., Oithona nana, Clausocalanus furcatus, and Temora stylifera were dominant during summer, whereas Oncaea sp., Calocalanus sp., Oithona nana, Clausocalanus paululus, C. furcatus, Parvocalanus sp., and Calocalanus elegans dominated the autumn and early winter populations. Sharing similar species with the Indo-Pacific region gives the copepod fauna of the Levantine Basin, at least in part, a subtropical affinity.