Purpose – The purpose of this paper is to examine the factors influencing e-procurement adoption in the United Nations (UN) system of organizations are examined. Design/methodology/approach – This paper reports on an extended multi-method case study of e-procurement in the UN. A three stage methodology is adopted – a questionnaire survey of UN organizations, case studies of e-procurement issues in three UN organizations, and an interactive workshop with the heads of purchasing of UN organizations. Findings – The paper finds that e-procurement is being used in the UN for transactions of routine, non-strategic purchases. UN development agencies are more likely to adopt e-procurement than humanitarian aid agencies as their operations are more predictable. The intention of the majority of UN organizations to adopt e-procurement within three years has been reversed following the workshop, which revealed that adoption of e-procurement would run counter to UN policies of supporting less developed nations, regions and organizations. A more cautious, “wait and see” approach has been taken rather than to unilaterally promote e-procurement across the UN system. Research limitations/implications – This research focuses on the UN, yet could have implications for other complex systems of organizations such as the public sector, or multinational companies considering implementing e-procurement with suppliers in developing countries. Practical implications – E-procurement needs to be considered in the context of other procurement policy objectives. What may be good e-procurement practice in a profit-making firm may be viewed as competing with broader policy objectives of not-for-profit organizations. The digital divide is a salient contextual factor for the UN, and brings about unforeseen issues regarding e-procurement adoption which may have resonance for other organisations. Originality/value – Much research on e-procurement has been conducted in the private sector and this paper contributes to the small but growing number of studies of e-procurement in the context of the public and not-for-profit sectors by studying e-procurement in the UN.