This study explores the concept of absorptive capacity of aid programs in health by focusing specifically on Global Fund grants. Based on the findings of the literature review, the main hypothesis of this study is that the absorptive capacity for Global Fund grants (dependent variable) is influenced by the level of governance, the overall level of funding for health, the level of development, the type of implementer, the disease component of grant, the number of grants managed by the recipient, the round of funding (year when grant was awarded) and the burden of disease in the recipient country (independent variables). This study also aims to investigate the effect of each of the independent variables on the level of funding absorption. These factors are analyzed individually and in various combinations, for example disease component (HIV/AIDS, Tuberculosis or Malaria). This study use a novel analytic method--qualitative comparative analysis--to analyze if, and to what degree, the absorptive capacity for Global Fund grants are influenced by the following factors: the level of governance, the overall level of funding for health, the level of development, the type of implementer and the burden of disease in the recipient country. The results of this study confirmed the complexity of absorptive capacity by demonstrating that there are multiple pathways to high and low absorptive capacity. The results are also surprising as it challenges the findings of the Literature Review related to factors associated with high and low absorptive capacity.