The aim of the diploma thesis is identified risks of reliability and credibility of selected manufacturing companies in Slovakia and based on analysis suggest ways to minimize risks. The content of the work is composed of 3 main parts. Theoretical part describes management, ethics, business ethics, ethics of managers, ethical credibility and risks. Research methodology is based on the introduction of the procedure for analysis of ethical credibility risks. In research is used an online questionnaire. Then we analyze answers of manufacturing companies and evaluate the results. Based on the results of the research, we propose measures. In the proposals for increasing ethical credibility, we present ways to minimize risks. The results of the diploma thesis will be used for Slovak Research and Development Agency in project APVV-17-0400 Enhancing the Ethical Environment in Slovakia (Institutional Procedures, Actors, Risks, Strategies).