Web usability for e-commerce sites becomes a more important issue as e-commerce gains its popularity. As for agricultural products, consumers are especially sensitive to the quality of information during transaction process. Successful e-commerce sites of agricultural products, such as Wine.com and Tesco, identified regular usability testing as part of key success factors. This paper aims to identify processes for evaluating usability for e-commerce sites of agricultural products and provide strategies to improve usability. The study aims to evaluate e-commerce usability of selected e-commerce sites using heuristic evaluation to provide objective e-commerce sites usability analysis for each transaction process.