The Science Museum has on permanent loan some 200,000 objects belonging to the Wellcome Trust. The collection reflects Sir Henry Wellcome's interest in a wide range of archaeological, historical, and ethnographic objects relating to the history of medicine. A small percentage of the collection is on display in the Wellcome Galleries at the Science Museum at South Kensington. The remainder is located in the Museum's Reserve Store in West London, where approximately 22,000 objects still remain in the 1,250 boxes in which they were transported to the Museum following cataloging at the Trust's premises in North London in 1977. Recently a two-year project was initiated by the Museum and funded by the Wellcome Trust to unpack, sort, and store the collection. This article discusses the planning, organization, and implementation of the project. It also highlights conservation issues which arose, including allocation of condition grades, treatment selection, and storage recommendations.