To examine effects of different rock failure criteria on stress magnitudes constrained from borehole breakouts, a real borehole breakout data set from a scientific ocean drilling project as a model case was used to constrain maximum and minimum horizontal stress magnitudes based on the Mohr-Coulomb and the modified Wiebols-Cook criteria. Comparison of the constrained stress magnitudes showed that effects of criterion on the constrained stress magnitudes were not negligible. © 2014 Taylor & Francis Group, London.