The Enron case raised an issue of the reliability of public accounting information in the U.S and gave a significant and negative impact on the international economy as well as on the accounting industry. As a result, the U.S. Government enacted a Corporate Accounting Reform so called Sarbanes-Oxley Act. Korea also consistently introduced Accounting System Enhancement Plans for the purpose of enhancing accounting transparency since 2003 and listed firms should adopt the Korean International Financial Reporting Standards since 2011. However, these regimes in providing high quality of accounting information and transparency are only focused on the listed firms which have many stake holders and mostly emphasize on regulations and restrictions. Therefore, to enhance accounting tranparency of non-listed small and medium sized enterprises, new systems related to small and medium sized enterprises are necessary to be suggested and supplemented. This study suggests incentive systems to improve accounting transparency of small and medium sized enterprises, not focused on regulations and restrictions. The incentive systems are summarized as follows. First, in the situations small and medium sized enterprises receive external auditing service from external auditors, expenses associated with auditing should be deducted in corporate tax. Second, we propose introduction of systems such as tax credit which reduce converting costs when small and medium sized enterprises voluntarily convert from Korean General Accepted Accounting Principles to Korean International Financial Reporting Standards. Third, we suggest introduction of tax incentive such as exemption of tax examination or corporation tax relief and installments when small and medium sized enterprises comply external auditing or internal accounting control system for a certain period. Fourth, some kinds of regimes such as increasing of criminal penalties for fraud, systems advising surrender, whistle blower protection for employees are should be introduced and government would make efforts to establish and complement these regimes for the purpose of adopting that systems well. In this study, we recommend the identified new incentive systems for enhancing accounting transparency of small and medium sized enterprises. Besides, this study has contributions to give assistance to Accounting System Enhancement Plans are extended to small and medium sized enterprises asides from listed firms.