Bilateral aid procurement is politicised and strongly favours suppliers from donor countries. Does multilateral development assistance eliminate the procurement bias favouring donor countries because international bureaucrats make procurement decisions? Existing evidence from the World Bank, which delegates procurement responsibilities to aid recipient countries, cannot answer our theoretical question. Using official data from 20 UN organisations during the 2013–2018 period and applying regression and mediation analysis, we find that the procurement of international organisations still favours donor countries when international bureaucrats make procurement decisions. We identify donor state representation within the UN staff as a key stepping stone linking donation to procurement bias. In contrast, member states whose nationals are heads of a UN bureaucracy do not enjoy procurement advantage, suggesting that UN procurement bias operates through an informal bottom-up channel. Our paper contributes to the debates on the independence of international organisations in the context of multilateral development assistance and procurement.