This study was carried out to determine the influence of fish oil supplementation on growth performance and some biochemical parameters of Ossimi ram lambs. Fifteen Ossimi male lambs were divided randomly into three groups (5 animals/treatment). The first group was fed the basal diet without any addition and served as a control. While the 2^nd (T1) and 3^rd (T2) groups were fed the basal diet supplemented with fish oil at levels of 1.5 and 3% dry matter (DM), respectively. Data were statistically analyzed using one-way analysis of variance GLM by SAS program.  The results revealed that the live body weight (LBW) and daily weight gains (DWG) were significantly (P ≤ 0.05) increased in the treated lambs compared to the control group. Concentrations of total protein, albumen, aspartate aminotransferase (AST) and alanine transferees (ALT) activities increased significantly (P ≤ 0.05) by given dietary fish oil than control diet. While, cholesterol was significantly lower (P≤0.05) in treated ram lambs than in those of the untreated ram lambs. In conclusion, fish oil supplementation at a rate of 1.5 and 3% DM to ram lambs improved growth performance and blood parameters.