Background: As a result of recent corporate scandals, several rules e.g. SOX have focused on the role played by Boards of Directors on the planning and monitoring of corporate codes of conduct. Non-executive directors are in a better position than executives to protect and further the interests of all stakeholders because of their experience and their sense of moral and legal obligations. Female directors also tend to be more sensitive to ethics according to several past studies which explain the fact that women are thought to place a greater emphasis on harmonious relations and the fact that men and women use different ethical frameworks in their judgments. The goal of this paper is to determine the influence of these characteristics of the Board in terms of promoting and hindering the creation of a professional code of conduct.

Methods: Research method of present study is descriptive with correlation-regression type. All companies listed in Tehran Stock Exchange were selected as the target population. From this population a sample of 202 was selected using random sampling. Necessary data for corporate governance were obtained from CODAL database. Then, contents of sample companies' website were analyzed in order to determine the creation of professional codes of conduct.

Results: Our findings show that a greater percentage of non-executive directors on a Board of Directors relate the creation of professional codes of conduct, positively. Moreover, the greater number of female directors lead to more ethical companies. Despite, board ownership does not necessarily lead to creation of professional codes of conduct.

Conclusion: In essence of corporate ownership structure and its relation on corporate governance it is highly recommended that professional standard-setting organizations urge companies to establish and use professional codes of conduct. Moreover, companies tend to use more female and outside directors on their boards.