An application of information technology in a company is important in order to make the company better. The information technology can support the achievement of the company's strategic plan to be aligned with its vision, mission and goals. Tabanan Primary Tax Service Office is a company as the example of the application of information technology for this research. The application in that company needs to be regulated, therefore it can be put to good use. In regulating information technology, an audit is needed which aims to evaluate and ensure compliance with the objective approach of a standard. The service audit in filing annual tax returns by using the COBIT 5 framework at the Tabanan Primary Tax Service Office is a form of audit to find out the IT processes that exist in the office. This audit was conducted to determine the level of maturity of the existing IT processes in the service of filing annual tax returns, whether it has been used properly and optimally based on COBIT 5. The audit analysis process performed to obtain capability results, such as the DSS 02, DSS 03, DSS 05, and APO 12 domains. Recommendations and suggestions for improvement of the results obtained are done using the COBIT 5 standard.