Over the last decades, Project management science shows increasing recognition and growth. The benefits to organizations are numerous and significant by the implementation of Project management, with the consequence that it becomes more and more popular in the business world. Nowadays, it is merely a fact that all projects involve risk. In other words, the zero risk project is not worth pursuing. That is the reason why risk management is considered today as an integral part of project management, a key process where most of the project managers know that is essential and prerequisite for good project management. More and more companies are now applying the risk management process in their projects, not only in order to predict the future, which is impossible, but also to improve their performance and increase their profits. This master thesis consists of two parts, the first is a bibliography research on risk management and the project risk management process, while in the second part, a risk analysis in a shutdown project of a refinery takes place as a case study. In order to examine the project risk, we proceed to both qualitative and quantitative analysis, with special attention to be given to the second one. Also, for the purposes of this study, two computer programs were used. The @Risk® of Palisade Corporation was applied to perform the quantitative analysis (Monte Carlo simulation, Sensitivity analysis) in the project, which was first modeled through dynamic scheduling with Microsoft® Project. The research was carried out from February 2015 to July 2015.