Two field experiments were conducted at the Experimental Farm, Sakha Agric. Res. Station , Sakha, kafrelsheikh,  Egypt during the two successive winter seasons of 2012/2013 and 2013/2014 to study the effect of four harvesting dates i.e 120,130,140 and 150 days after sowing and retting methods (Retting in water change every 24 hours and Still water retting) on yield and its quality yield components of three flax Genotypes (Sakha 3, Ilona and S. 541 /D/10 ) The experimental design was split plot with four replicates where in field experiment, the three genotypes were distributed in the main plots and harvesting dates were allocated in the sub plots, while after harvesting the twelve combinations between the genotypes and harvesting were distributed in the main plot while the two retting treatments were allocated in the sub plots. The results revealed high significant differences among the flax genotypes in straw yield and its components. Sakha 3 cultivar registered  the greatest values of technical length, straw yield/plant and straw yield/fed., sakha 3 and Ilona cultivars gave the highest values in fiber strength, fiber fineness, fiber percent, fiber yield /plant and fiber yield /fed. while S. 541 /D/10 genotype was the highest in stem diameter, fruiting zone length, number of capsules/plant, number of seeds /plant, 1000-seed weight, seed yield / fed. and seed oil content.       The results revealed that the harvesting flax plants at 140 DAS gave significantly increases in technical length and fruiting zone length in both seasons. While, the same effect was in seed yield /plant& straw yield /fed. in the second season and in both seed yield /fed. and straw yield/ plant in first season, on the other hand the traits of fiber length, fiber strength, fiber fineness, fiber percent, fiber yield /plant and fiber yield /fed. recorded the highest significantly values at harvesting date 140 DAS in both seasons and did not significantly differed with  harvesting date 150 DAS in fiber length in both seasons and in fiber yield /fed. in the second seasons. However, delayed harvesting date to 150 DAS showed the highest values in number of capsules/plant, number of seed /plant, 1000-seed weight (g), seed yield /plant, seed yield /fed. straw yeild/fed.  seed oil content in both seasons and straw yield/plant in the second season. While, The harvest date at 130 DAS recorded the highest values in stem diameter in both seasons compared with other harvesting dates. The interaction between the genotypes and harvesting dates had a significant effect in technical length, fiber strength, fiber fineness, fiber percent, fiber yield /plant, fiber yield /fed. fruiting zone length, stem diameter, number of capsules/plant, number of seed /plant, 1000-seed weight, seed yield /plant , seed yield /fed., straw yield/plant straw yield/fed. and seed oil content in both seasons. The twelve combinations between genotypes of flax and harvesting dates recorded significant differences in fiber fineness, fiber length, fiber strength, fiber percent, fiber yield /plant and fiber yield /fed. in both seasons . The combinations between both sakha 3 and Ilona genotype and the harvesting date at 140 DAS recorded the highest values in all previous characters  both seasons, Without significantly differences with the combination between harvesting date 140 DAS and S. 541 /D/10 genotype in the fiber yield/fed. character.   The retting method recorded significant differences in fiber length, fiber strength, fiber yield /plant and fiber yield /fed. in the second season only. While the characters of fiber fineness and fiber percent recorded the significant differences in both seasons. The retting method with water change every 24 hours recorded the greatest significantly values in fiber length, fiber strength, fiber fineness, fiber percent, fiber yield/plant and fiber yield/fed. The interaction among the twelve combinations between flax genotypes with harvesting dates and two retting method had a significant effect in fiber fineness in the first season, fiber yield/ fed. in the second season  and fiber percent & fiber yeild/plant in both seasons . From the results and under the conditions of this study, it could be concluded that for producing the high seed and fiber yield, it can be recommended by S. 541 /D/10 and sakha 3 genotypes and harvest at 140 DAS with retting by water change every 24 hours for high quality of fibers.