Two field experiments were conducted at the Agricultural Research and Experiment Center Faculty of Agriculture at Moshtohor, Kalubia Governorate, Egypt; during 1989 and 1990 seasons. The target of these investigations was to study the effect of topping dates (at 36 days and 50 days ages), and nitrogen levels (30, 60 and 90 kg N/feddan), as well as their interaction on the yield, yield components and fiber properties of cotton cv. Giza 75. Results indicated that topping treatments signifiantly decreased plant height, seed cotton yield per plant and per feddan as well as lint yield per feddan. However, topping at 50 days ages gave the highest values in number of monopodia per plant as compared with the control (without topping). Meanwhile, topping treatments had no beneficial tEfect on yield compcents and fiber properties. Plant height and number of green boils/plant signifi— cantly increased by increasing N level up to 90 kgs N/feddan. Whereas, nitrogen levels did not aff&et yield, yield component or fiber properties of cotton cv. Giza 75.