In this work, the End Notched Flexure (ENF) test is analyzed in order to obtain the critical strain energy release rate in mode-II fracture of bonded joints. A cohesive model based on specially developed interface elements, including a linear softening damage process, is employed. The adequacy of the experimental ENF test is evaluated by numerical simulation. The objective is to compare the critical strain energy release rate in mode-II (G(IIc)) obtained by different data reduction schemes with the real value which is an inputted parameter in the cohesive model. The effect of the Fracture Process Zone (FPZ) ahead of the crack tip is evaluated. A crack equivalent concept is proposed in order to account for the energy dissipated in the FPZ. A data reduction scheme avoiding the need to measure crack length is proposed. A good agreement with the inputted value of G(IIc) was obtained.