Two field trials were conducted at the Experimental Farm of Sakha Agricultural Research Station in Egypt for the 2021/2022 and 2022/2023 seasons, to evaluate the performance of some flax genotypes (Strain 651 (S.651), Sakha 3, 5 and Giza12) under different nitrogen fertilizer sources; ammonium sulfate (20.6% N), ammonium nitrate (33.5% N) and urea (46.5% N). For the experiment design, split-plot design was used with four replicates. Three different nitrogen fertilizer sources were allocated to the main plots, while four flax genotypes were allocated to the sub-plots. The results indicated that the use of ammonium sulfate treatment achieved significantly highest values for most of the studied traits, followed by ammonium nitrate treatment, whilst using urea recorded the lowest ones during both seasons. The results also, referred that S.651 was significantly superior to the rest of other genotypes in technical length, fiber length, fiber percentage and fiber yield/fed within both seasons. Giza12 recorded significantly the most beneficial results for stem diameter,straw yield/plant, straw yield/fed, fruiting zone length, seed index and seed yield/plant over both seasons. Moreover, Sakha 5 significantly outperformed other genotypes in number of capsules/plant, seed yield/fed, oil percentage and oil yield/fed during the 1^st and 2^nd seasons. Consequently, this study recommended the usage of the nitrogen source of ammonium sulfate or ammonium nitrate with the promising flax strain S.651 to obtain the highest fiber yield/fed, or with Sakha5 the oil type cultivar to gain the highest seed and oil yield/fed in Northern Delta region of Egypt.