The United Nations and other multilateral organizations have always been prominent in the health field. UN agencies like the World Health Organization (WHO), however, have come increasingly under the influence of major individual donors which provide earmarked funding. Since 2000, two major vertical funds in the health field – the Global Fund and the GAVI Alliance – provide new models of multilateralism and their funding patterns, together with those of WHO, are examined in some detail. We review the extent to which the two new funds and WHO conform to traditional definitions of multilateralism by reference to several test areas: degrees of concentration of funding sources; the influence of individual funders; sustainability; and transparency. We also draw lessons from the analysis for the UN development organizations.