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Forage maize has become a major constituent of ruminant rations in recent years. Application of appropriate nitrogen fertilizer can improve forage yield and quality and also increase animal performance and has a potential to reduce production costs. This research was done to determine the effects of nitrogen fertilizer on yield and total protein of forage maize at Research Farm, Faculty of Agriculture, Islamic Azad University, Khorasgan Branch (Esfahan). Randomized complete block design with three replications was used. Nitrogen levels included 0, 40 and 60 kg/ha. The nitrogen fertilizer was provided from urea source (46% pure N). Nitrogen had significant effect on plant height, stem diameter, LAI, leaf fresh yield, stem fresh yield, leaf dry yield, stem dry yield, leaf dry weight/stem dry weight, total fresh yield and total dry yield; however, the number of leaves per plant was not significantly affected by nitrogen. Even though nitrogen had significant effect on total protein, protein yield, nitrate and organic carbon, there was no significant effect of nitrogen on leaf protein, stem protein and ash percentage. The highest LAI, total fresh yield, total dry yield and total protein were obtained with application of 60 kg N/ha, but the difference in total protein between 40 and 60 kg N/ha was not significant. The highest LAI, total fresh yield, total dry yield, leaf protein, stem protein, total protein, ash percentage, nitrate and organic carbon were obtained with application of 60 kg nitrogen/ha, but in this treatment the maximum nitrate content was also achieved which caused adverse effect of nutrition quality. The appropriate nitrogen fertilizer, which is useful to obtain not only high forage quantity, but also maximum nutrition value, was applied with 60 kg N/ha in low input nitrogen farming.