This study was performed to assess the combined effects of three salinities (0, 20 and 38 ppt) and three acclimation temperatures (15, 20 and 25 degrees C) on growth performance, proximate composition and thermal tolerance of European Sea Bass (32 g) inhabiting southern parts of the Mediterranean Sea. Highest fish final weight (83.8 g) was achieved at 25 degrees C in freshwater (FW). Specific growth rate (SGR) at 25 degrees C was about twice higher than that at 15 degrees C, while 20 degrees C promoted an intermediate growth. The fish cultured in FW at 25 degrees C displayed consistently lower FCR and better SGR than those in full strength seawater (SW). Salinity had strong influence on fillet protein and lipid compositions. Highest lipid content (14.9%) was found in fish held in brackish water (20 ppt), and the fish held in SW had the lowest lipid content. CTMin and CTMax values ranged from 3.26 degrees C to 7.33 degrees C and from 31.81 degrees C to 36.68 degrees C, respectively. The thermal tolerance results indicated that European sea bass is more sensitive to high rather than low temperatures. These results suggested that this species can be farmed in stagnant SW deep ponds with high ambient temperatures during hot summer months in southern parts of the Mediterranean. During cold winter months, however, this fish can be successfully cultured in low salinities or even in FW.