Both nitrogen supply and planting date affect plant development, yield and other characteristics of cotton. To obtain this type of information the response of Giza 75 cotton variety to N  fertilization ( 0, 20, 40, 60, and 80 N unit / fed. ) and planting dates (15^thMarch, 1^stApril, 15^th April and 1^st May ) were studied at the Agric. Exp. and Res. Cent. Fac. Agric. Cairo Univ. during 1995 and 1996 seasons. The main findings of this study can be summarized as follows: sowing date and nitrogen level had significant effects on plant height in different growth stages in the two seasons. Generally delaying sowing date led to significant  decrease in plant height Like-wise increasing nitrogen levels resulted in increasing plant height. Sowing date had insignificant effects on LAI at the three growth stages studied ( 8-leaves, first  flower and first open boll). However, increasing nitrogen fertilization more than 40 N unit/fed. induced significant increase in LAI. Delaying sowing date, led to significant decrease in the total dry matter (TDM). Increasing the applied nitrogen level, increased significantly the average (TDM ). In general  there was a gradual increase in DM partition in terms of recovered roots, leaves and stems with late planting . However , late planting induced significant reduction in DM. partition in terms of the fruiting parts of its (buds, flowers and bolls) and in estimates of earliness criteria (1^stflower and 1^st open boll ) . Cotton yields and only one yield component variable viz.: number of bolls per plant and earliness index expressed significant variation in the favour of the earlier sowing dates viz.: 15^th March and 1^st April , with no significant differences  between those two dates in most instances . All yield components except number of bolls per plant and standability at harvest were not significantly affected by variation in levels of N fertilizations used. Averaged over the levels of the other factor, both successively latter planting dates and nitrogen levels  exhibited insignificant variations in all fiber properties, indicating that these traits are highly inherited traits and low effected with variability in the environment.