Recently the interest in sustainable and environmentally friendly initiatives has increased dramatically in the hospitality industry due to a growing concern to protect the environment, as well as other numerous reasons. Although hotels implementing environmental certifications expect to obtain large benefits, disadvantages and challenges also exist for hoteliers to establish an environmentally responsible business. Therefore, this study aims to have a closer look at the advantages and disadvantages that a hotel can obtain from implementing environmental certifications such as the ISO14001 and EMAS, which, in this case, the research is a single case study of a particular hotel, the Barcelona Princess Hotel. The main purpose is to analyze the specific outcomes from the implementation of green certifications from a managerial and employee perspective, and to provide some suggestions to increase the hotel’s environmental management and performance. In order to achieve the study aim, a mixed strategy of quantitative and qualitative research is undertaken. This case study uses a triangulation approach as it is based on multiple sources of evidence. The methods applied are a semi-structured interview to the General Manager, questionnaires to the employees and document analysis. The findings show a wide range of benefits in different aspects that hoteliers can obtain from implementing EMS and ISO14001 standard, as well as the main disadvantages and challenges the hotel has to face. Moreover, the findings also found some differences between both the managerial and the employee perspective; and it provides with recommendations and conclusions for hoteliers to develop a more efficient environmental management. The thesis concludes by giving recommendations for further research, which summarizing, encompass studies about benefits from implementing environmental certifications from different perspectives (stakeholders or customers), studies regarding the size of hotels, and finally, research taking into account the continent in which the study is being focused.