Two field experiments were carried out at Tag El-Ezz Research Station Farm, Dakahlia Governorate during the two successive seasons of  1996/1997 and 1997/1998 , to study the effect of two potassium levels i.e. , 20 and 40 kg  k₂0/faddan and the three nitrogen fertilizer levels of 30 , 50 and 70 kg/faddan on the two flax varieties namely Giza 8 and Viking . The results of this investigation could be summarized as follows:   1-Viking flax variety surpassed Giza 8 with significant differences concerning plant height, technical stem length, straw yield/plant, straw yield/faddan, fiber yield/plant and fiber yield/faddan in both seasons. 2-Applying 40 kg k₂o/faddan caused remarkable increases in straw yield and its components previously mentioned in comparison with the lowest potassium dose 20 kg/faddan in the two successive seasons. 3- There are gradual increases in all the six straw characters studied with increasing nitrogen fertilizer level from 30 up to 70 kg/faddan in both seasons. 4-The flax variety Giza 8 was superior over Viking in number of fruiting branches/plant, number of  capsules/plant and seed yield/plant as well as faddan in the first and second seasons . 5- All the four seed characters under study increased with increasing potassium fertilizer  level from 20 to 40 kg k₂o/faddan . 6-Fertilized flax plants with 50 kg N/faddan achieved highest mean values of seed yield and its components . 7-The maximum biological yield obtained by Viking variety when compared with the results got by Giza 8, but, the latest variety gained highest estimates regarding the economic yield and harvest index in both seasons. 8-The greatest estimates of biological yield, economic yield and harvest index resulted by adding 40 kg k₂o/faddan . 9- Biological yield/faddan increased with increasing nitrogen level from 30 to 70 kg/faddan, while the intermediate N level ( 50 kg N/faddan ) caused highest estimates in economic yield and harvest index characters in both seasons . 10-The estimates of correlation coefficient (r) were highly significant and positive between fiber yield/faddan and each of straw yield/fad., fiber yield/plant , straw yield/plant, plant height and technical stem length , also the relationship between   straw yield/faddan and each of fiber yield/plant , straw yield/plant , plant height and technical stem length . Moreover , the associations between seed yield/faddan and      each of seed yield/plant, no., of fruiting branches and no. of capsules/plant were highly significant and positive , the same degree of significance had observed between either fiber yield/plant and each of straw yield/plant , plant height and technical stem  length or between straw yield/plant and the two latest characters previously mentioned .