It is well known that demagnetizing effects arising in samples of finite length may drastically modify the magnetic response of superconductors. In this work we report the study of how demagnetizing effects influence the response of finite superconductors of cylindrical and orthorhombic shape in the Meissner state. We have measured both the ac susceptibility and dc magnetization of a set of niobium samples with different dimensions. We compare the experimental results with calculations from a model based on energy minimization in the superconductor. A good agreement is observed for a wide range of sample sizes. © 2000 Elsevier Science B.V All rights reserved.