The effects of diets containing peanut oil at different ratios on growth performance, biochemical and fatty acid compositions of juvenile European seabass, Dicentrarchus labrax, were evaluated under controlled conditions in the recirculated system for 12 weeks. The trial was planned as 6 groups (18 tanks) with three replicates and stocked as 12 fish (mean weight ~4.72±0.01 g) in each tank and was fed by one of six experimental diets. Each diet was formulated to replace 0% (FO, control), 20% (PNO20), 40% (PNO40), 60% (PNO60), 80% (PNO80) and 100% (PNO100) of the fish oil with peanut oil.