In numerical assessments of concrete bridges, the value of the concrete fracture energy GF plays an important role. However, mostly the fracture energy is only estimated based on the concrete compressive strength using empirical formulae. In order to study methods to determine the concrete fracture energy for existing bridges, tests were carried out on 55-year-old concrete from a bridge tested to failure in Kiruna in northern Sweden. Uniaxial tensile tests are performed on notched cylindrical concrete cores drilled out from this and other bridges. In the paper, different methods to determine the concrete fracture energy are discussed and recommendations are given for assessment procedures.