The aim of this study is to examine the effects of optimal and suboptimal N fertilizer levels in saline conditions on pepper plant and to predict the yield, soil water and drainage water EC and ETa using UNSATCHEM. The salinity effect on pepper plant biomass was statistically significant. Increasing salinity led to increase in dry weights. At optimal N level, yield decreased above EC 2 dS/m. At the sub optimal N level a significant decrease in yield occured above EC 4 dS/m. Ca accumulation in leaves decreased above 2 dS/m salinity. Chloride accumulation in leaves increased with increasing salinity after 2 dS/m salinity level with optimal and fertilizer sharply increasing in Cl. Salinity level and N treatments did not statistically affect accumulation of Na, Mg and K. Our results clearly show that if there are more than one stress factors, in our case salinity and nutrition, the stronger stress tends to obscure the other stress factor. On the other hand at higher salinity levels the salinity stress is dominant with respect to yield and response is similar for both N levels. Based on our results we also concluded that under saline condition (higher than threshold for given crop) there is no need for optimal fertilization because the main stress factor is salinity. We provide a comparison of drainge water EC and volume and soil water salinity with UNSATCHEM simulations.