Nitrate (NO3) toxicity due to excessive nitrogen (N) fertilization in forage crops is one of the most important nutritional concerns in forage production. The aim of this study was to evaluate the effects of increasing rates of N fertilizer on the NO3 content of forages obtained from five triticale (xTriticosecale Wittmack) cultivars, harvested at three growth stages. These stages included stem elongation, booting and maturity (in straw), which correspond to the different utilizations possible in animal feeding. The experiments were carried out under dryland field conditions by applying increasing rates of N (0, 40, 80 and 160 kg ha(-1)) in a split-plot design with four replicates in two years. Forages were sampled to analyze the NO3 concentration in triticale cultivars at stem elongation, booting and straw according to maturity stages. From the results of the analysis of variance conducted in both investigation years, it was found that N fertilization rates, cultivars as well as their interactions had significant (P<0.01) effects on NO3 concentrations of triticale cultivars at different growth stages. The results of the study showed that the NO3 contents of the forages increased in accordance with increasing rates of N in both years and the NO3 concentrations of all cultivars peaked at 160 kg N ha(-1). In both years, the accumulated amount of NO3 found in the triticale cultivars differed according to the growing year, the stages of the forage sampling, and the rates of applied N. Nitrate concentrations accumulated to their highest amount at the stages of stem elongation and booting for the Karma 2000 variety in the first year and the Presto 2000 variety in the second year and also, Karma 2000 had the highest NO3 concentration in the second year in straw. Although triticale cultivars did not accumulate NO3 to the critical level of intoxication (NO3 concentration > 1000 ppm in the dry matter), it can be suggested that caution should be exercised when using Karma 2000 as a forage crop. As the growth period progresses, NO3 concentration had a tendency to decrease. The decline was greater at maturity than at the booting stage. In conclusion, this research indicates that when drinking water and other feed materials do not contain high level of NO3, there is no danger posed from using the triticale cultivars tested in this research for feeding livestock.