The HIV-AIDS epidemic is one of the most challenging and significant health crises facing the world today. In order to cope with its complexities, the United Nations and World Health Organization have increasingly relied upon the resources offered by networks of HIV-AIDS nongovernmental organizations (NGOs). The research reported here uses evolutionary theory to predict the patterns of alliances and collaborations within the HIV-AIDS International Nongovernmental Organizations (INGO) network. The hypotheses are tested using 8 years of data from the Yearbook of International Organizations. The results showed that geographic proximity and common ties with intergovernmental organizations (IGOs) predict the pattern of alliances among HIV-AIDS INGOs. The best predictor of such alliances, however, is past relationships among these organizations.