This masters thesis deals with the management system audits of the OMV E&P department. The thesis analyses the actual used audit system of the HSEQ department, and compares them with the regulations stated in the ISO norms and with the methods used by other E&P companies. Since the management system and the auditing methods used in the HSEQ department have been installed some time ago, they were originally designed for a much smaller company and should be investigated for their ability to comply with the demands of the international business sector. The thesis is structured in mainly two parts. In the theoretical part, the basis for the work is documented, while the practical part contains the survey and the according analysis. In the end the findings of the work are summarized, and some recommendations for improvements in the OMV auditing system are given. The theoretical part starts with the definition of the terms Management and management system. Coming from there, the management process is described in detail. After explaining the function of the controlling circle, the audit, which is a major part of the controlling circle, is described by explaining the complete process of an audit. After the description of some international norms important for this thesis, the data acquisition by survey is explained. This part contains a description of the survey phase model, and a comparison of different survey methods. In the end the methods for question formulation are explained. The practical part of the thesis starts with the connection between the theoretical survey methods, and its realization. After a short description of the response rate, the analysis starts with a general interpretation of all questions of the survey. In the detailed analysis, the participants of the survey are divided according to their size, and differences between the groups are investigated. The last part of the thesis contains the comparison of OMV auditing methods with the survey results, and another comparison with according international norms. The thesis ends with a summary of the findings and recommendations for the OMV auditing system.