Online shopping in open markets becomes increasingly popular with the development of the Internet. The purpose of this study is to formulate and evaluate critical success factors in the open market from the perspective of buyers. Based on an extended technology acceptance model, this study assumes that the success of open markets are influenced by several factors, including perceived website quality, perceived usefulness, third party recognition, satisfaction, and trust. An empirical survey is conducted and questionnaires are collected from the respondents who had experience in using the open markets. The hypotheses are verified by using the structural equation modeling. Testing results are summarized and managerial implications are discussed.