The importance of this study is that as decision making in entrepreneurship is instantaneous, cognitive biases will have a direct influence on the decision making process and consequently, on failure and success of the entrepreneurs and their businesses. The current study has been conducted with a qualitative approach and the purpose of reducing the experience of failure in early stage entrepreneurs and enhancing entrepreneurial decision making will study and evaluate the mental models of national excellent entrepreneurs and the positive and the negative effects of cognitive biases on the decision making process of the entrepreneurs. Therefore, it is important to emphasize this issue. Our statistical sample consists of 11 national excellent entrepreneurs who have experienced the failure at least for once. The data collecting tool was semi structured interview with entrepreneurs in person or on the phone. The analysis of data was done in two phases. The role of the biases in the first and the second stage of the business life cycle is studied. Eventually, the result of the study is classifying entrepreneurs’ cognitive biases in four groups including: the main biases, motivators, common biases, and disincentive biases of entrepreneurship. This classification is done based on the experiences of entrepreneurs about cognitive biases.