In this paper, the bending fatigue behaviour and damage development during fatigue of polyurethane (PUR)-epoxy 3D woven sandwich composites is investigated. 3D sandwich fabrics are produced by a velvet weaving technique. It allows relatively easy production of delamination-resistant sandwich panels, compared to more traditional sandwich structures with honeycomb or foam cores. In this paper, the 3D sandwich fabrics made of glass fibre are impregnated with epoxy resin while the empty core can be foamed up with PUR to improve shear resistance of the panels. Core properties and static bending strength of the panels were evaluated. Three-point bending (3PB) fatigue tests were performed on four different materials (two unfoamed epoxy panels and two PUR foamed epoxy panels) with varying static properties. After fatigue testing, the Wohler curves for each panel were determined. The relation between the observed damage development, the property degradation during bending fatigue and the static properties of the panels was investigated. (C) 1998 Elsevier Science Ltd. All rights reserved.