High transaction costs have been cited as limiting access to credit in developing countries. This issue is much more critical for knowledge-based companies due to their position in accelerating economic growth and the particular characteristics of these companies. Therefore, this research aims to evaluate the transaction cost of financing knowledge-based companies from an official fund in Iran that provides financial support for innovations and technologies. The data was collected through interviews and questionnaires in a sampling of knowledge-based companies in 2022. In this study, after calculating the transaction costs of financing, the effect of the factors affecting it has been investigated. The investigated sample was 123 companies from the fund's customers. The results showed that, on average, the ratio of transaction cost to the facility, transaction cost rate, total cost rate (transaction cost and interest rate), and the ratio of transaction cost to interest rate are equal to 3.33, 7.04, 15.66, and 0.81, respectively. Based on the results, the facility amount, the number of payment steps, the distance between the request for the facility and the contract, the interest rate, and dummy variables for the type of facility have a positive and significant effect on the transaction cost
