Twenty-four flax genotypes {21 promising lines and 3 check varieties, Giza 8 (oil type), Sakha 1 (dual purpose type) and Sakha 3 (fiber type)} were evaluated for straw, seed, oil yields and their related traits under two different environments (Sakha Exp.Station, Kafr El-Sheikh Governorate "clay soil" and Ismailia Exp.Station, Ismailia Governorate "sandy soil") through two successive seasons, 2008/09 and 2009/10. These materials were evaluated in a randomized complete block design with three replications at the two above-mentioned locations. The collected data indicated that, Genotypes mean squares were highly significant for straw, seed, yields/fed and their related traits. The genotype x year variance (s²gy) was less than the genotype x location variance (s²gl) for all characters, except plant height and oil percentage. Consequently evaluation should probably stress using more locations but testing over a shorter period of times. Heritability values (H%.) in broad sense were high for plant height and two important components of seed weight (seed index and No. of capsules/plant). Also, the observation of narrow range between phenotypic (PCV) and genotypic (GCV) coefficients of variability, which gave almost similar values of PCV and GCV in plant height was mainly due to genetic differences as evidenced from the very high heritability. Also, straw weight per plant and long fiber percentage as well as the two important components of seed showed similar results, indicating possibility of using these yield components (seed index and No. of capsules per plant) in selection index for improving seed weight per plant as well as plant height to improve straw weight per plant. Concerning mean performance and susceptibility index as affected by environmental stress for sandy soil, line 541-C/3 exhibited high yielding potential with high tolerance for straw and fiber yields per fed, but this line exhibited moderate tolerance for both seed and oil yields per fed. Also, line 541-D/10 exhibited high yielding ability with moderate tolerance to sandy soil conditions for each of straw, fiber, seed, and oil yields per fed. Hence the two promising lines, 541-C/3 and 541-D/10 may be consider good substitutes for the low yielding ones, Giza 8, Sakha 1 and Sakha 3 in future after evaluation in more location before releasing as a new Egyptian flax cultivar and may be useful as potential breeding material for releasing cultivars to sandy soil conditions (suitable to grown in sandy soil) for fiber and oil "dual purpose".