The world's grain stocks are providing more world market stability than they did prior to 1978. Even though the volatility of world grain production increased since 1978, global consumption volatility declined. Grain production variability in the Soviet Union, United States, and Argentina appear to be major potential sources of instability to world grain markets, though much production variability in the Soviet Union and the U.S. is offset by their own stock adjustments. U.S. stocks have played a major stabilizing role on world grain markets. EC grain stocks in recent years have also played a stabilizing role. Reductions in U.S. and EC grain stock levels, a possible result of trade liberalization talks, could have important implications for market stability in the future.