This paper uses the interval and fuzzy finite element method for the eigenvalue and frequency response function analysis of structures with uncertain parameters. In order to reduce the calculation time of the interval and fuzzy analyses, these non-probabilistic methods are combined with the component mode synthesis technique. Special attention is paid to the effect of uncertainties on the mathematical description of this substructuring technique. All concepts are illustrated through a benchmark structure example. (c) 2006 Elsevier Ltd. All rights reserved.