Rice, one of the most important food crops for humans, is the first crop plant to have its genome sequenced. Rice whole-genome microarrays, genome tiling arrays and genome-wide gene-indexed mutant collections have recently been generated. With the availability of these resources, discovering the function of the estimated 41,000 rice genes is now within reach. Such discoveries have broad practical implications for understanding the biological processes of rice and other economically important grasses such as cereals and bioenergy crops.