Seasonal occurrence and absolute density of chironomid midge populations were studied in the reclaimed rice fields in Seosan, Korea, using emergence traps from April to September in 1997-1999. Total 24 species, 12 genera were collected, of which Polypedilum nubifer was predominant, followed by Chironomus kiiensis, Tanytarsus sp. 1, Cricotopus sylvestris and Cricotopus oryzaphagus. Populations of Po. nubifer, Ch. kiiensis and Tanytarsus sp. 1 occurred through April-September, with the peak density in late June for Po. nubifer and Tanytarsus sp. 1 and in early July for Ch. kiiensis. In cases of Cr. sylvestris and Cr. oryzaphagus, populations appeared from late April-eayly May and completely disappeared in late July and thereafter, with a Peak in mid-late June. The absolute numbers of population densities throughout a season (May- September) in average of 1997-1999 were $5,1541/m^2$ in Po. nubifer, $2,170.5/m^2$ in Ch. kiiensis, $1,990/m^2$ in Tanytarsus sp. 1, and $12,310.5/m^2$ in all Chironomids. It was estimated that total 1,245,945,705,000 adults of Chironomidae emerged from the reclaimed rice fields (10,121 ha) in Seosan throughout the season (April-September) in average of 1997-1999.