Rice hybrids with a yield advantage of about 10-15% over best inbred varieties were introduced in China in mid 1970s and are now planted to about 45% of the rice land in that country. Rice hybrids adapted to tropics have now been bred at IRRI and by NARS and show similar yield advantage. The increased yield advantage of tropical rice hybrids is due to increased biomass, higher spikelet number and to some extent higher grain weight. Increased adoption of hybrids in the tropics should contribute to increased productivity.