The synergistic effect of arachidonic acid (ARA) (20:4n-6) and α-tocopherol on the accumulation of fatty acids and the peroxidation of lipids in liver and muscle was evaluated in Atlantic salmon (Salmo salar) juveniles. Triplicate groups were fed during 12 weeks with eight experimental diets with different levels of ARA and α-tocopherol. In all experimental diets the productive parameters were not affected (P > 0.05). ARA accumulation in muscle and liver showed significant differences (P < 0.05) between treatments. The synergic relationship between ARA/α-tocopherol was influenced (P < 0.05) only in the liver, showing that high levels of α-tocopherol and ARA favored the fatty acids accumulation in this organ. Results indicate that a dietary concentration up to 0.6% ARA, the increment of α-tocopherol is not necessary. The data obtained in this study demonstrated that the interaction between the ARA and α-tocopherol influenced the accumulation of fatty acids in the liver.