Two field trials were carried out at El- Gemmeiza Agricultural Research Station, Garbia Governorate, during the two successive seasons 2006/2007 and 2007/2008. The objectives of this research was aimed to study the performance of some flax varieties i.e. Sakha 2, Sakha 3, Sakha 4 and Giza 8 under different sowing dates  on 20^th October, 10^th  November, 1^st December and harvesting dates after 135, 150 and 165 days from sowing and their effects on straw yield and its component. The main findings could be summarized as follows. Early sowing on 20^th October significantly increased plant height, technical length and main stem diameter in the first season and straw yield/ plant , straw yield/ faddan in the second season, fiber yield/ faddan, fiber langth and fiber fineness in both seasons. Sowing flax on 10^th November significantly increased straw yield/ plant and straw yield/ faddan in the first season compared with the other sowing dates. Sowing flax on 1^st December significantly decreased all studied straw characters. Delaying harvesting date to 150 days from sowing significantly increased straw yield/ plant, fiber yield/ plant, fiber yield/ faddan. Delaying harvesting date to 165 day from sowing significantly increased plant height, technical length, fiber length, straw yield/ faddan and fiber fineness. Sakha 3 variety surpassed the other varieties in plant height, technical length in the first season, fiber yield faddan and fiber length.  Sakha 4 variety gave the tallest technical length in the second season and fiber yield/ plant in both seasons. Sakha 2 and Giza 8 varieties surpassed the other varieties in the straw yield/ faddan. Giza 8 superior other varieties in main stem diameter in both seasons. It could be concluded that sown Sakha 3 or Sakha 4 early when shown early on 20^th October and harvesting it after 165 days from sowing  maximized straw/ fad and fiber fineness under the environmental conditions of Garbia Governorate.