Abstract This investigation focuses on the relationship between the deformation behavior of semi-brittle materials tested in uniaxial and flexural geometries. It has been shown that flexural load-displacement data exhibit no detectable non-linearity until a significant volume of material has been plastically deformed near the region of maximum stress. Therefore, determination of yield stress from load-displacement data in bending and the assumption of an elastic stress distribution will give in general a 70% overestimation of the value measured uniaxially. By combining experimental and numerical analyses, a correction procedure has been developed for materials that display work hardening behavior which allows for the approximation of uniaxial yield stress from flexural load-displacement data. The cast irons tested here show that a tension-compression asymmetry can also be easily taken into account with this method.