The Green Revolution has enabled rice production to meet the demands of the growing population. Since 1990, however, rice production has increased at a lower rate than the population. This deceleration in the growth of rice production is a cause for concern in terms of world food security. It has been the topic of numerous reviews and several rice scientists have alerted those concerned o the risk of a pending food crisis. Yield gaps can still be observed in several countries, while evidence of a productivity decline in intensive rice production has been inreasingly noiced both on resea'ch stations and in farmers' fields. An increase in rice yield can lead to improved farmers' income and food security. Because of the complexity of this problem, different points of view exist regarding the possibility of narrowing yield gaps as a tool for increasing rice production. Several experts believe that yield gaps in favorable rice ecosystems are not significant for improving rice yield poential. Others believe that large and exploitable rice yield gaps still exist. In 1998, the average rice yields in 81 countries were less than the world average yied of 3.8 t ha/-1, idicating the existance of yield gaps. Progressive farmers usually obtain higher yields and more profits than ordinary farmers, indicating the presence of knowledge gaps. The yield gap in rainfed rice, usually larger than in irrigated rice, suggests the potential for increasing production.