CERES-Rice model was used to simulate growth and yield of four common rice varieties in Thailand with the attention on rate and timing of N application, a factor that most limits crop yield. The model predicted slightly higher grain yield than that observed for all varieties at N input of 75 kg/ha, but the differences between observed and simulated yields were not significant, except for varieties HSP and SPR90. The simulated grain[ratio ]straw ratio was significantly higher than the observed value for all varieties except that of HSP. There was no significant difference between the simulated and observed values of days to flowering. Generally, the model reasonably predicted the phenology and yields of RD23 and KDML105 varieties. The model was also used to compare the yields of KDML105 variety as influenced by rate and timing of N application grown in acid sulphate soils. There was a variation in predicted biomass yield with applied N rates at 0 and 150 kg/ha, but timing of application had no effect. In Aeric Endoquept and Sulfic Tropaquept soils at Suphan Buri and Pathum Thani rice research stations, the yield patterns remained unchanged and showed a positive response to N rate up to 75 kg/ha. The model estimated higher grain yields beyond 75 kg N/ha while the observed yield decreased. Based on the simulated yields for a 10-year period at the Asian Institute of Technology (AIT), Pathum Thani, Suphan Buri, Nakhon Pathom and Ratcha Buri rice research stations the varieties were ranked as: SPR90 > RD23 = HSP > KDML105. The model suggested that SPR90 is the most suitable variety for the central plain and its potential yield ranges from 4030 to 5600 kg/ha. Pathum Thani province, with acid sulphate soils, had the lowest potential for rice production.