In recent years, bioenergy has drawn attention as a sustainable energy source that may help cope with rising energy prices, but also maybe provide income to poor farmers and rural communities around the globe. Rising fuel prices, growing energy demand, concerns over global warming from GHG emissions and increased openness to renewable energy resources, domestic energy security, and the push for expansion into new markets for crops in the face of world trade outlooks are all factors driving interest in expanding bioenergy use. Potentially adverse impacts from a rapid bioenergy expansion include upward pressure on international food prices, making staple crops less affordable for poor consumers; potentially significant adverse impacts on both land (soil quality and fertility) and water resources; and on biodiversity and ecosystems, in general. Given the numerous and high level of uncertainties regarding future biofuel supply, demand, and technologies, the paper examines three alternative scenarios: a conventional scenario, which focuses on rapid global growth in biofuel production under conventional conversion technologies; a second generation scenario, which incorporates a ‘softening’ of demand on food crops due to 2nd generation, ligno-cellulosic technologies coming online; and a ‘second generation plus scenario’, which adds crop productivity improvements to the second generation scenario, which essentially further reduce potentially adverse impacts from expansion of biofuels. Impacts of global biofuel development and growth on rural poor can be both positive and negative. Biofuel crops do not necessarily crowd out food crops, at least not under the alternative scenarios examined here. Instead there is room for complementarities and synergy and rural agricultural development and socioeconomic growth can go hand-in-hand with enhancement of bioenergy production capacity.