The paper compares different aggregates of aid financed global public goods and detects the presence, for the period 1995-2006, of the substitution effect between these aggregates and traditional aid that was found by former studies for earlier periods. A second focus of the paper is on the differences in the importance that donors attach to the various types of global public goods, trying to detect regular patterns in their choices of financing. Statistical regularities, representative of common historical, social, cultural factors, for groups of countries (Anglo-Saxon, Northern European and Central European) give rise to the existence of a certain clusterized homogeneity in global public goods financing. Potential explanatory variables are examined in a panel analysis, which reveals the dominance of the donors’ wealth, preferences for public goods and public finance constraints in the decision of aid funding of global public goods. Finally, there is evidence that some global public goods with weakest-link technologies have become increasingly important at the global level. The increase in their financing through aid flows could be explained by the rich countries’ fear of an insufficient provision by poor countries, which, increasingly, cannot afford to pay for them: rich countries are therefore stepping in to avoid sub-optimal levels of provision, as already foreseen by Sandler (1998).