Whole soybean has 19 percent ether extract and 42 percent CP and is used as a high energy-protein supplement for early lactation dairy cows, but the protein is highly degradable, so small amounts of amino acids can reach the small intestine to meet high amino acid requirements in early lactation. Therefore, various chemical and physical treatments have been suggested to decrease ruminal protein degradability. The practical use and application of any one method to lower ruminal feed degradability is dependent not only on its efficacy but also on its cost effectiveness, safety and ease of application. For these reasons, heat treatment is the most commonly used physical method. Energy expenditure and fixed costs are lower for roasting than for oven treatment, thereby warranting further research on this type of heat treatment (Plegge et al., 1985). The purpose of this study was to determine how roasting of soybeans affect Met and Lys plasma levels (as the first limiting amino acids in milk yield) in early lactation cows.