Resource conservation technologies (RCTs) involving various tillage and seeding practices such as no tillage, direct-seeding and bed-planting have potential to improve the sustainability of the rice-wheat system. The impact of RCTs on yield and N dynamics in the rice-wheat system was evaluated in field trials conducted at Ludhiana and Modipuram, India; Meherpur, Bangladesh; Ranighat, Nepal; and Lahore, Pakistan for 3 yrs during 2002-2006. The RCTs gave similar wheat yield (3.3 – 3.7 Mg ha-1) but reduced rice yield by 0.9 to 1.3 Mg ha-1 compared to the conventional practice. The Crop Estimation through Resource and Environment Synthesis (CERES)-Rice and CERES-Wheat models, embedded in the Decision Support System for Agrotechnology Transfer (DSSAT) version 4.0 framework, were evaluated using the data from the above trials. Genotypic coefficients for rice and wheat cultivars used in these trials were derived in this study. The models simulated the phenology of rice and wheat crops satisfactorily in all the locations (R2 between simulated and observed days to flowering and maturity for rice were 0.75* and 0.64*, and for wheat 0.84* and 0.88*, respectively). Predicted grain yield of rice in the puddled transplanting treatment agreed well with observed yields (R2=0.69*) but there was poor prediction (R2=0.36) when yields of direct-seeding and bed planting of rice were considered. Predicted grain yields of wheat, however, agreed well with observed yields in all the tillage and seeding practices (R2=65*). There was good prediction (R2=0.65*) of N uptake by wheat but prediction of rice N uptake was poor (R2=0.07). The study suggested that wheat can be satisfactorily grown with various RCTs but for rice the RCTs need refinement to improve yield. The CERES model was able to capture the major effects of crop management with RCTs on rice and wheat yield but needs improvement for estimation of N uptake by rice.