A study was conducted at giza Agricultural Research Station in 1999/2000 and 20002001 growing seasons with the following objec­tives: (1) screen some flax genotypes for powdery mildew resistance. (2) determine the potential productivity of such genotypes, (3) define the genetic basis for powdery mildew resistance, yield and some yield-related trails, and (4) assess the type and the degree of association be­tween powdery mildew intensity rating and each of yield and yield-related traits. All possible crosses without reciprocals were made among the four parental genotypes Dakota, Written, Cortland, and Linore. Dako­ta and Wilden were highly resistant to powdery mildew, while Cortland and Linore were highly susceptible. The paretnal genotypes and their F1 six populations were subjected to (liegel crossing program analysis for the following traits: total plant length, technical stem length, fruiting zone length, number of basal branches/plant, seed yield per plant, straw yield per plant, disease intensity variables (disease incidence and disuse severity) at two dates. Significant differences in all the traits wore ob­served among the parental genotypes. Highly significant mean squares of general combining ability (GCA) were observed for all the trails. Sig­nificant differences for specific combining ability (SCA) were observed for most of the traits. GCA was greater than SCA for most of traits indi­cating the predominance of additive gene effects in the inheritance of most of the traits. Powdery mildew resistance in flax was not a simple in-!miter, trait; therefore, parental contribution should be carefully investi­gated before incorporation into a breeding program for powdery mildew resistance. Correlation analysis showed that total plant length was nega­tively correlated (P50.10) with each of the early and the late disease in­cidence, while straw yield/plant was negatively correlated (P10.10) only with the late disease incidence. Seed yield/plant showed highly signifi­cant (P10.01) positive correlation with the early disease incidence and siginificant (Ps 0.05) positive correlation with each of the early and the let disease severity. Those results suggest that selection for War type flax would result In an increase in powdery mildew resistance. while selec­tion for seed type flax would result in a decrease in such a resistance.