There is extensive duplication of accessions among collection holders globally. To save costs, unwanted duplication should be avoided. This issue has been addressed internationally. In Europe, there are currently 35 Brassica collections located in 24 countries. Duplication may be identified not only by surveying passport data and seed transactions, but also by applying morphological or genetic characterization. Our study included two collections; one at the N. I. Vavilov Institute of Plant Genetic Resources in St. Petersburg (VIR) and one at the Nordic Genetic Resource Center (NGB). A random set of 13 accession pairs or triplets of cabbage, turnip and swede were selected on the basis of identical or similar accession names. The accessions could potentially be regarded as duplicates. Morphological characterization showed that in about 50% the pair/triplet, the accessions were identical and should thus be regarded as duplicate holding. Determining the status of the remaining accessions, which were more or less distinct but had identical or similar names, was more difficult. In this paper, possible explanations for the similarities in names are discussed, as is the need to include characterization in any duplicate assessment process.