Asymmetric structural foams were prepared by compression molding to study the flexural properties of these sandwich structures with different layer thickness. It was found that the flexural properties of asymmetric structural foams are function of load direction. Since the bending behavior is a combination of tension and compression, the stress distribution across the foam core plays a key role in describing their bending properties. The experimental results show that the compression modulus of integral foams is lower than its tensile modulus. Based on this information, a model is proposed to predict the flexural properties of asymmetric structural foams based on stress distribution. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 113: 3103-3112, 2009