About 90% of world’s rice is produced and consumed in Asia. Nearly 50% of total rice producing area is irrigated. This area produces over 70% of the total grain. This paper discusses the concept of sustainability in the context of irrigation in rice-growing Asia, identifies major factors which affect sustainability, and analyzes relevant trends and concerns. It is argued that environmental degradation in the upper watershed of irrigation systems causing excessive sedimentation in their reservoirs and canal networks, waterlogging of low-lying areas caused by inefficient system design and management, and declining trends in the productivity of intensively cropped ricelands are the processes that pose serious threats to irrigation sustainability. Recommendations for research and actions to alleviate the major constraints to Asian irrigation sustainability have been made.