The effect of dietary protein and fiber on growth and metabolic parameters in blood serum, liver and kidney were determined in a 2 × 5 factorial experiment involving 40 Sprague-Dawley rats. Treatment variables were two dietary protein levels (16 and 24%) and five acid detergent fiber levels (6, 10, 16, 24 and 34%). No difference in growth rate of rats was found due to varying levels of either protein or fiber in the diet. Increasing the dietary protein level from 16 to 24% resulted in an 18.5% reduction in blood cholesterol. The dietary treatment containing 16 % fiber influenced most metabolic parameters examined, including blood serum cholesterol, liver cholesterol and total lipid content in liver and kidney. Rats receiving the diet containing 16% fiber had the highest serum cholesterol (88.9 mg/dl) and the lowest liver cholesterol (4.4 mg/g) as compared with other fiber groups