With growing concerns for sustainable development world over, planners of natural resources are focussing their attention on vulnerability arising from availability and use of water resources. Past studies of water resource vulnerability have either been too aggregate, or have focussed on one single dimension of these issues. This study presents a comprehensive analysis of global (using national scope) water resource-based vulnerability (WRV) using a joint criteria of water availability and its relative use. Vulnerability status for each country was assessed for the present (1990) situation, as well as for the year 2025. Four factors were taken into account to determine the nature of the WRV for a country: population growth, food self-sufficiency, industrial development, and climate change. World population growth, which is projected to increase to 8.45 billion people by the year 2025, by itself would trigger 40% of the population residing in countries facing some degree of WRV. Combined with food self-sufficiency, industrial growth, and climate change, by the year 2025, some 5.1 billion (60% of the total world population) would live in regions potentially experiencing moderate to extreme WRV. The study suggests that the regions that are at great risk are those already facing some degree of WRV; the climate change would most likely accentuate the already worsening situation in many regions, while improve it in regions that are not projected to be vulnerable.