The Millennium Seed Bank (MSB) Partnership, developed and managed by the Royal Botanic Gardens, Kew (RBG Kew), conserves propagules primarily from orthodox seed-bearing wild vascular plants. It is the largest ex situ conservation programme in the world, currently involving 96 countries and territories. Where possible, seeds are collected and conserved in the country of origin with duplicates being sent to RBG Kew’s MSB for storage. In this paper we assess the conservation value of the germplasm stored at the MSB using both quantitative and qualitative methods.