The PMI is a globally recognized institute, dedicated to Project Management. It develops guidelines and standards that present techniques and tools to generate better results in projects. The most famous and sold standard is the PMBOK Guide; it is divided into 10 different areas with their respective activities. It is imaginable that by having enough credibility, this guide would be strictly followed, however, it is not what is indicated in a survey by Mangelli (2013), where a low use of the PMBOK Guide was discovered. Therefore, this study aims to identify the reasons of the low use of this guide. This paper presents an exploratory and qualitative research, where seven people were interviewed, all of them with experience in project management within the Oil and Gas market in the city of Rio de Janeiro. The results showed that the PMBOK Guide is well known in the project management market and the use of it occurs in two forms, formal and informal. Furthermore, the commonly used practice identified in this study differs from what was found by Mangelli (2013). Another finding of this study was the perception that the PMBOK Guide is not easy to apply, is automated, mechanized and that its practices are confusing, detailed. Moreover, it was also possible to notice the predominance of experience before the knowledge of the guide. Finally, it was identified that the certificates issued by PMI are not seen as a difference in career, they are valued for people in early career, but for the most established and experienced professionals, they do not make much difference for professional growth.