Water deficit stress acconts for a major part of annual crop losses including oilseed crops. This research was aimed at studying growth, chlorophyll, proline and soluble carbohydrate contents, yield and yield components of flax genotypes under different moisture regimes. A 3-replicate split plot RCBD field experiment was conducted at the Lavark Research Farm, College of Agriculture , Isfahan University of Technology, Isfahan-Iran, in 2009. Three levels of irrigation based on evaporation from the standard after 75 mm, I 2 as moderate drought=irrigation after 115 mm evaporation and I 3 as severe drought=irrigation after 145 mm evaporation served as main plots. Six flax genotypes consisting C 1 , C 2 , C 3 , B, Khorasan and 33 were considered as sub plots. Leaf Area Index (LAI) at early flowering stage, chlorophyll content at anthesis, proline and soluble carbohydrate content of leaves and plant height at 50% capsule formation stage, capsules/plant, seeds/capsule, grain yield, oil percent and yield, biological yield and harvest index were measured while plant height suffered a 12% decrease under sever drought, C 1 and B genotypes indicated smallest and greatest plant heights, respectively. LAI was negatively affected by drought, leading to an average of 1.58 at I 3 , against 3.12 at I 1 . Khorrasan produced greatest LAI. Irrigation regimes differed in terms of chlorophyll content, a 17/5% decrease observed under severe drought. C 3 and 33 genotypes indicated greatest and smallest chlorophyll content, respectively. Drought increased leaf proline and soluble carbohydrate content by 174.6 and 21.42%, respectively. C 1 and B genotypes produced greatest and smallest proline contents, respectively. Genotype B indicated greatest increase in soluble carbohydrate content. Grain yield at I 3 was 36.28% lower than at I 1 , due apparently to the smaller capsules/plant (23.05%), seeds/capsule (6.43%) and seed weight (11.6%). The greatest and smallest grain yields were observed with B and C 3 . Irrigation regime did not affect seed oil percent significantly, thoug the oil yield was 40% decreased due to severe drought. The highest (781.04 kg ha -1 ) and lowest (273.4 kg ha -1 ) oil yield were observed with genotypes B and C 3 , respectively. Irrigation regime left significant effect on biological yield, with I 1 (5796.1 kg ha -1 ) outyielding I 3 (3982.9 kg ha -1 ). It could be concluded that, drought affects flax growth and grain yield Key Words : flax, drought, proline, soluble carbohydrate, chlorophyll, yield