The problem dealt with in the paper is ecological certificates. First, ecological certificates in general are referred to and then examples of ecological certificates in tourism and hospitality are stated. The paper focuses on the application of ecological certificates in the business activities of hotel companies. Due to the impact that human activities have on the climate and the environment, the need to protect the planet we live on and to reduce or minimize negative effects is becoming more and more evident. Among others, hotel companies implement ecological programs in their operations as well, and as a result of the fulfillment of ecological criteria, they have been awarded with ecological certificates, which are a proof of performing their business operations in harmony with nature. The desire to hold ecological certificates and thus the desire to distinguish themselves from others and acquire competitive advantage encourages hotel companies to undertake various measures that contribute to environmental protection and minimizing the negative effects of their business. The application of measures, which at the same time represent a condition for obtaining the certificate, achieves effects on the operations of hotel companies primarily in the form of cost reduction in the long term as well as in the form of conquering a new market segment and creating a positive image in the public. The aim of the paper is to explain and analyze ecological certificates in detail, especially those applied in the field of tourism and hospitality. Furthermore, the goal is also to present the measures taken in order to run sustainable business on the specific example of a hotel and to detect how these efforts made in the area of sustainability are evaluated and recognized by the certification association.