Contrary to the opinions expressed by many commentators, the recent episode of higher prices for agricultural commodities is likely a transitory phenomenon. When compared to the last half-century, population growth is expected to be much slower in the coming decades, with nearly all of the growth occurring in lower income countries, where added population places less pressure on global markets. The impact of the recent surge in growth rates in the developing world, and the associated dietary upgrading, will be insufficient to overcome the population effect. Further, earlier projections of biofuels growth are proving overly enthusiastic in the wake of lower oil prices and environmental concerns. Consequently, our projections using the SIMPLE model of global agriculture suggest that, in the long run, food prices are expected to be slightly lower at mid-century than they were prior to the food price crisis (2006). However, this outcome is shown to depend critically on the rate of productivity growth in agriculture. Our projections involve expected global productivity growth over the 2006–2050 period which is only 60% as fast as over the historical period: 1961–2006. If total factor productivity growth slows more than this, perhaps due to adverse climate impacts or reduced investment in R&D, then prices could rise in the coming decades. Also, we cannot rule out the possibility of a steeper price decline in the wake of recent signs of robust productivity growth in the developing world.