From June 2003 to May 2004, the precipitation at Changshu Agro-ecological Station (31 degrees 32'45" N, 120 degrees 41'57" E) of Chinese Academy of Sciences was collected to monitor its particle- and dissolved nitrogen and phosphorus concentrations, with the seasonal variation of nitrogen and phosphorus in wet deposition in Taihu Lake region investigated. The nitrogen input from wet deposition had an obvious seasonal variation, being higher in summer and spring and lower in autumn and winter. The ratios of dissolved nitrogen (DN) and particle nitrogen (PN) to total nitrogen (TN) in wet deposition were 88.2% and 11.8%, and those of dissolved phosphorus (DP) and particle phosphorus (PP) to total phosphorus (TP) were 53.3% and 46.7%, respectively. The amounts of nitrogen and phosphorus deposited into Taihu Lake region by light and medium precipitation were higher than those by heavy precipitation. The annual input of TN and TP from wet deposition was 30.2 kg x hm(-2) and 1.1 kg x hm(-2), respectively, and the DN concentration in all precipitation events as well as the DP concentration in 92.5% of precipitation events was higher than the thresholds of inland water eutrophication.