The purpose of this study was to describe temporal variations in the abundance of cladocerans in the Mediterranean Sea in relation to environmental parameters. The study was conducted between 2008 and 2011 at five sampling stations located in the coastal waters of Iskenderun Bay. Zooplankton samples were seasonally collected for four years using a 200-mu m mesh WP-2 zooplankton net. The contribution of cladocerans to the total zooplankton community was 22.8% in 2008 and 9.3% in 2009. In 2010 (59.4%) and 2011(63.4%), the annual mean abundance of cladocerans increased markedly from 473 ind. m(-3) to 3917 ind. m(-3) and accounted for more than half of the zooplankton population. A total of five species of Cladocera were found: Penilia avirostris Dana, 1849, Pseudevadne tergestina (Claus, 1877), Evadne spinifera P. E. Muller, 1867, Pleopis polyphaemoides (Leuckart, 1859) and Podon intermedius Lilljeborg, 1853. Penilia avirostris was the most abundant species during all seasons, especially in April and July, for all four years of the study. The abundance of total cladocerans and P. avirostris was negatively correlated with salinity (p <0.01) and picoplankton abundance (p <0.05). P. avirostris also exhibited a positive correlation with phytoplankton abundance (p <0.01), as well as with E. spinifera. In addition, the abundance of E. spinifera and P. tergestina was positively correlated with temperature (p <0.01), but P. tergestina correlated negatively with chlorophyll a. In conclusion, species composition and abundance of cladocerans seems to be greatly affected by the amount of available food and other environmental factors, such as temperature and salinity.