Existing methods for the determination of the elastic modulus of eggshell depend on static measurements. In this work, dynamic measurements are performed in order to determine the elastic modulus of a shell segment. A test procedure was developed, which excites a shell segment and measures its resonant frequency. This resonant frequency together with the dimensions of the shell segment form the base for the calculation of the dynamic elastic modulus. A formula for the elastic modulus was derived using modal analysis of a shell segment. The elastic modulus of 100 Hisex(R)-layer eggs was measured to validate the technique. For each egg, three shell segments were sawn along the equator. The average value for the modulus of the eggs was 28.55 GN m(-2). The variance between the modulus of the eggs was 3.070 GN m(-2). These values are in line with the values of the static modulus mentioned by other investigators. Furthermore, the variance between measurements on the same shell segment was 49.7 MN m(-2) indicating that the test procedure provides repeatable measurements. (C) 2004 Silsoe Research Institute. All rights reserved Published by Elsevier Ltd.