The present study is concerned with a numerical analysis of the uncertainties in the response of foam core sandwich structures caused by the uncertain microstructure of the core material. In the sense of an integrated computational materials engineering type approach, a three-step procedure is proposed. In the first step, the effective material properties of the core material are computed. For this purpose, a probabilistic homogenization procedure is adopted for the prediction of all elastic constants together with their probability distributions as well as all spatial correlations and interrelations between the individual parameters. In the second step, a random field model for the core material is derived, based on the homogenization results obtained in the first step. The random fields are found to reproduce all stochastic features of the uncertain core material in a proper manner. Using the random field description as an input for a Monte-Carlo-type structural analysis, the uncertainties in the stiffness and strength of sandwich structures are computed in the third step. The capabilities of the proposed procedure are demonstrated using the example of a single edge clamped sandwich beam under transverse loads. (C) 2014 Elsevier Ltd. All rights reserved.