Concrete cover for reinforcement is required to protect the rebar against corrosion and to provide resistance against fire. The methods for measuring cover thickness are based on many equipment and techniques, whose performances are related to their basic principle, and which give access to the following information: cover (thickness, accuracy), reinforcement diameter, presence of adjacent reinforcements and recognition of the steel profile. Different NDT methods are available for different applications. Each NDT methods has its pros and cons. In selecting an effective test method, special attention should be given to the limitations of the method for field investigation. In this report, we will present two techniques that are used in a variety of engineering projects. These techniques are magnetic methods using concrete cover meter and Ground Penetrating Radar (GPR). This report includes two parts which summarizes the round robin non-destructive testing and evaluation (NDE) for concrete cover depth measurements. In the first part, we present a literature review about the importance of having an adequate concrete cover depth, the requirements for the concrete cover depth and state-of-the-art cover depth measurement devices. In the second part, we present an international Round Robin test program with the purpose of testing the electromagnetic and GPR based methods on the thick-walled concrete mock-up. The report presents also results from the Round Robin measurements.