Two field experiments were carried out at Gemmiza Res. Station, Gharbia Governorate, Agric. Res. Center during  the two successive seasons of 2004/05 and 2005/06 to study the response of six flax genotypes namely Sakha 1, Sakha 2, 402/2/5/10, 420/140, 329/2/18 and S.336/2/1/2 to the three NPK fertilizers i.e., 0 control, (45 kg N + 15 kg P₂O₅ + 24 kg K₂O / fed) and (60 kg N + 30 kg P₂O₅ + 24 kg K₂O / fed). Split plot design with four replications was used.  The results of this investigation could be summarized as follow: 1-     The flax variety Sakha 1 recorded maximum mean values and surpass the other genotypes concerning straw yield / fed as well as per plant, plant height, technical length and fiber yield / fed, while S.336/2/1/2 recorded lowest estimates for most economic straw traits. 2-     The flax variety Sakha 2 ranked first and superior the remain genotypes regarding all studied seed characters i.e., seed yield / fed as well as per plant, no. of capsules / plant, no. of seeds / capsule, no. of seeds / plant and no. of apical branches. 3-     Application of NPK fertilizer caused  gradual increment in all straw and seed yields in addition to their components with increasing NPK level from 0 control towards the highest level. 4-     The interaction between genotypes and NPK levels had significant effect on straw yield / fed, fiber yield / fed, seed yield / fed, no. of capsules / plant and no. of seeds / capsule. 5-     The correlation coefficients between plant height and each of technical length and straw yield / plant were highly significant and positive, the r value between technical length and straw yield / plant was only significant and positive. The relationships between no. of apical branches and each of no. of capsules / plant, stem diameter and straw yield / plant were positive and highly significant, but it was positive and only significant with no. of seeds / plant. The r values between no. of capsules / plant and each of stem diameter, straw yield / plant, seed yield / plant, no. of seeds / plant and fruiting zone length were highly significant and positive.              In general, it could be summarized that the flax variety Sakha 1 cultivated for high straw and fiber yields. While Sakha 2 for seed and oil yields, it must apply 45 kg N + 15 kg P₂O₅ + 24 kg K₂O / fed to the two flax varieties for obtaining highest yield. The breeder must take care plant height for high straw and fiber yields in addition to no. of capsules / plant for seed yield.