In the Netherlands research has been performed on the Observational Method, aiming at a wider use of the method in the design of underground and infrastructural construction works. This paper summarizes the guideline that was output of the research, providing a clear definition, an overview of obstacles and pre-conditions, practical recommendations on how to make a safe design while using the principles of Observational Method within the context of the Eurocode 7 and practical recommendations on how to organize the method during construction.