This investigation was conducted at Gemmaza  Agric. Res. Station Gharbia Governorate, A.R.C., Egypt during the two successive seasons of 2003/04 and 2004/05 to study the effect of inoculation with bio-fertilizer on yield and yield components of two commercial cultivars namely Sakha1 and Sakha2 under graded levels of nitrogen fertilization. A spit-split plot design with four replications was used with varieties (V), Sakha1 and Sakha2 as main plots, whereas mineral nitrogen (N) levels (0,15,30 and 45 kg/fed) as sub plots while the sub-sub plots were devoted to bio-fertilization (B) treatments. The most important results could summarized as follow: 1- Combined data revealed that significant difference between flax cultivars for all characters under study. Sakha1 gave the highest values of plant height, technical stem length, straw weight / plant, straw yield / fed, fiber yield / fed, fiber percentage, fiber length and fiber fineness, while Sakha2 gave the highest values of each No. of capsules / plant, No. of seeds / capsule, 1000-seed weight, seed weight / plant seed yield / fed, oil yield/ fed and oil percentage. 2- The nitrogen fertilizer showed significantly increased most characters under study by  increasing nitrogen level from zero to 45 kg N / fed, while there was no significant effect on No. of seeds / capsule. Whereas, fiber fineness gradually decreased as N level was increased. There was a trend of coarseness of fiber due to increased N level until 45 kg N / fed. 3- Bio-fertilizer application significantly increased  plant height, technical stem length, straw weight / plant, straw yield / fed, fiber yield / fed, No. of capsules / plant, No. of seeds / capsule , 1000-seed weight, seed weight / plant, seed yield / fed, oil yield / fed and also, the bio-fertilization significantly increased oil percentage fiber percentage and fiber length. In contrast, bio-fertilizer caused decreases in fiber fineness. 4- The interactions between the studied factors were not significant, except N x V interaction had a significant effect on straw weight / plant, 1000-seed weight, fiber percentage and fiber length. Moreover,  V x N x B for straw weight / plant, straw yield / fed, fiber yield / fed, No. of capsules / plant, 1000-seed weight, seed weight / plant, seed yield / fed and oil yield / fed. It can be recommended that cultivation of flax with soil inoculation by bio-fertilizer with nitrogen level of 30 kg N /fed in order to get of the highest straw yield and fiber yield with Sakha1 as well as get of the highest seed yield and oil yield /fed with Sakha2 under the environmental conditions of the study.