Boron is one of the seven recognized essential micro nutrients required for the normal growth of most plants. B deficiency in plants is most wide-spread. The deficiency of B has been reported for many crops in many countries of the world. The role of boron is especially important in the calcareous soils because CaCO3 content reduces the availability of this nutrient, fixes, in the soil, and slows down its uptake by plants. At present boron is routinely recommended for cotton grown on calcareous soils of the cotton growing regions. The influence of boron on fiber development would suggest an effect on fiber quality. The present study was conducted to cover the following topics: 1. Status and dynamics of boron in some Egyptian soils. 2. The combined effects of boron fertigation and soil sulphur application on the growth, yield and elemental composition of cotton as a test crop cultivated by seeding or cutting method and grown on calcareous soil. 3. The critical levels of boron in cotton leaves and in soil.