Two field experiments were carried out at Kafr El-Dawar Centre, El-Beheria Governorate, Egypt, for two seasons to study the effect of nitrogen fertilization and organic manure, i.e farm yard  Manure (F.Y.M) and Chicken Manure (C.M) on cotton plants.                 The experiment included 7 treatments which were control, 30 kg N/fed., 60 kg N/fed., 24 m³ F.Y.M../fed, 12 m² F.Y.M./fed + 30 kg N/fed, 8 m³ C.M/fed and 4 m³ C.M/fed + 30 kg N/fed. The results could be summarized as follows : -        The treatments had a significant positive effect on N,P,K and Cu leaf contents but no significant effect on Mg, Fe and Mn leaf contents in both seasons, but on Zn leaf content in one season only. -        In most cases, 30 kg N and 60 kg N/fed increased leaf nutrient contents significantly compared with the control. -        In most cases, leaf nutrient contents were increased significantly by using organic manure with or without nitrogen. -        Applying F.Y.M at the rate of 12 m³/fed + 30 kg N/fed as ammonium nitrate applied in one dose after thinning increased significantly final plant height, number of fruiting branches/plant, seed cotton yield/fed. and its components in both seasons. -        It can be concluded, that F.Y.M was more effective than chicken manure. Meanwhile organic manure + nitrogen proved to be more effective than organic manure alone on growth and cotton production especially the treatment of 12m³ F.Y.N./fed + 30 kg N/fed.