The dietary intake of omega-3 polyunsaturated fatty acids has emerged over the past 20years as an important way to modify cardiovascular risk. The present study aimed to evaluate the possible effects of a partial replacement of soybean meal in control economic diet by different concentrations of fish oil on the possible harmful changes in histological structure of liver and kidney and blood parameters in rabbits. A total of 36 adult New Zealand rabbits were equally divided into four groups, (control diet and control diet supplemented with different concentrations of fish oil at levels of 0.5, 1.0 and 1.5mL fish oil per day/kg live body weight) and dissected after 6weeks. Our results showed that, feeding diet supplemented with fish oil were significantly increased the percentages of hemoglobin, platelets, the mean corpuscular hemoglobin, WBCs count, total proteins, albumin, albumin/globulin ratio, _SGOT and testosterone and significantly decreased the total lipids, cholesterol and triglycerides. The used of fish oil are good supplements for growing rabbits without any adverse effect on histological structure of liver and kidney in rabbits.