Two field eXperiments were carried out during 2003(2004 and 2004! 2005 seasons to study the effect of some intercropping patterns of barley with sugar beet under three levels of N fertilizer on yield and yield components of sugar beet and barley. The intercropping patterns were planting barley on sugar beet beds (120 cm wide) in 3, 4 and 5 rows; representing 37.5, 50 and 62.5 % of the barley sole crop < /p> which was grown on eight rows. N levels were 60, 60 and 100 kg Ni fed. Sugar beet was planting on the bed representing 100 % of sole crop. A split plot design was used with three replications. The obtained results could be summarized as follows: Sugar beet : lntercropping systems significantly reduced root length, root diameter, root weight, roots yield and sugar yield! fed with increasing number of intercropping rows of barley. Increasing N fertilizer levels from 60kg Nifed up to 100kg Nifed significantly increased root length, diameter, weight and sugar yield! fed. Interaction effect of intercropping barley with sugar beet recorded the highest values for the previous traits with intercropping system of 3— rows and adding 100 kg N! led, while the lowest values were recorded with intercropping 5- rows and adding 60 kg N! fed. Barley : lntercropping systems significantly reduced plant height, spike length. number of grain/spike, grains weightlspike and weight of 1000 grains with increasing number of intercmpping rows of barley. On the other hand, grains and straw yield.l fed were increased by increasing number of intercropping barley from 3- rows up to 5- rows. Increasing N fertilizer levels from 60 kg led up to 100 kg N ifed significantly increased all the previous traits of barley. The highest values for weight Le. 1000- grain, grains and straw yield! fed with intercropping system of 5 rows and adding 100 kg N! fed, while the lowest values were recorded with intercropping 3 rows and adding 60 kg N! fed. Competitive relationships: Land Equivalent Ratio (LER) was increased by 42 — 55% when barley intercropped with sugar beet over monocultures of both crops. Relative Crowding Coefficient (RCC) of sugar best and barley increased with the pattern of 3-rows which gave the highest RCC value (2276) whereas the lowest value was recorded with pattern of 4-rows (11.98). Sugar beet plants had positive values of aggressively (dominant crop), Whereas barley had negative effect (dominated crop) under the three intercropping systems.