Recent advances in studies on long-term changes in precipitation amount and its characteristics in the world and its regional aspects are reviewed. According to the IPCC Fourth Assessment Report (IPCC, 2007), global annual land precipitation has increased about 1.08-1.10 mm per decade since 1901. Precipitation amount mainly increased in middle and high latitudes. Increases in winter precipitation are obvious in Eurasia, North America and northern Europe. On the other hand, decreasing tendency are observed in southern Europe, northern Africa, and South and Southeast Asia. There is no evident trend in Oceania and Central America. Although a long-term increasing trend is seen in the global land average precipitation, there are distinct decadal-scale temporal variations in precipitation time series. It is expected that precipitation characteristics, such as precipitation frequency, and intensity, will increase because of an increase in the water holding capacity of the atmosphere in a future warmer world. Changes in precipitation characteristics have been investigated in many regions around the world. The frequency of heavy precipitation has tended to increase in several countries in the middle and high latitudes during recent decades. In Central America and the Caribbean region, interannual variations related to SST variations in the tropical Pacific and the tropical Atlantic were observed. The contribution of very wet days to annual total precipitation across the globe has sharply increased in recent decades. However, daily precipitation data used for investigating on the precipitation characteristics are very limited, particularly, in African and Southeast Asian regions. Thus, the long-term changes in precipitation characteristics presented in a number of recent global and regional reports are not very reliable for these regions. Data rescue activity, particularly, for the first half of the 20th century is urgently needed in such sparse data regions, as Africa and Southeast Asia.