 The world's total water footprint related to crop production in the period, 1996-2005 was 7404 billion cubic meters per year, 78% green, 12% blue, 10% gray. Wheat and rice have the largest blue water footprints, together accounting for 45% of the global blue water footprint. A relatively large total blue water footprint as a result of crop production is observed in the Indus River Basin, 117 GM3 year minus 1, and the Ganges River Basin, 108 GM3 year minus 1. This article was authored by M. M. Mekonen and A. Y. Hoekstra.