Abstract Fatigue crack nucleation at grain boundaries near the endurance limit was examined combining the results of the fatigue tests with local orientation measurements and with finite element (FE) calculations. Bicrystals and coarsegrained thin sheets were examined in which the orientation and inclination of each boundary could be measured directly. These results were used as input for the FE calculation in which the stress concentrations near the boundaries were calculated. In the fatigue tests, the boundaries, at which the first cracks nucleate, where measured by a replica technique. A comparison of the experimental results with the predictions of the FE calculation yields that the cracks nucleated and propagated along the boundaries with the largest stress concentration. Cracks which hit a boundary with a lower stress concentration either stop or propagate transgranularly, depending on the local stress concentration given by the microstructure. From these results, it can be concluded that elastic strain incompatibilities combined with the microstructure (grain size and orientation) can be used to predict the crack nucleation sites and the scatter in lifetime for fatigue near the endurance limit.