The collection at Gordailua is constantly growing and the centre has its own programme of acquisitions. Other offers of donations, sales or temporary loans from individuals and organisations are also considered.
Acceptance depends on a series of criteria: consistency with the collection's mission, contribution to existing pieces, state of conservation, representativeness of a specific period, territory, social sector, etc. In the case of offers of sale, the price must be proportionate to the heritage value of the item.
Proposals are analysed regularly by an inter-institutional commission, comprising two technical officers each from the provincial government and the San Telmo Museum, to ensure coordination and consistency in providing a unified vision of the collection housed at Gordailua.