Goksu Delta is a specially protected area in the Mediterranean region of Turkey. The delta is classified as a Wetland of International Importance according to the RAMSAR Convention on Wetlands of International Importance. Increases in population have recently taken place in this region due to heavy agricultural activities and discharges of anthropogenic wastes. In the present study, frequencies of erythrocytic nuclear abnormalities such as, micronuclei (MN) and nuclear buds (NB) were investigated in peripheral blood of three fish species; Clarias gariepinus (Catfish), Alburnus orontis (Bleak), and Mugil cephalus (Mullet) from Akgol (AG) and Paradeniz (PD) lagoons of Goksu Delta. Concentrations of heavy metals (Cu, Cd, Ni, Pb) were also measured in the water, sediment samples. MN and NA frequencies were elevated in fish from AG and PD lagoons in comparison with those from upstream regions. The results of this study indicate that the lagoons of Goksu Delta contaminated with genotoxic pollutants and that the genotoxicity is related to the agricultural activities and to the discharge of anthropogenic waste waters.