Phosphorus is the second limiting nutrient after nitrogen. It is the one of the key nutrient and sways the early crop development and tuber initiation, tuber size, tuber specific gravity. Final tuber yields are a function of tuber set, tuber growth rate and the duration of tuber growth. Phosphorus influences potato growth and yield in several ways. Management of phosphorus is a critical component in potato production systems as potato has relatively high P requirement and it inefficiently uses soil P. Phosphorus promotes rapid canopy development, root cell division, tuber set, and starch synthesis. Adequate P is essential for optimizing tuber yield, solids content, nutritional quality and resistance to some diseases. Phosphorus use efficiency of potato is lesser (10-15 % approx) as it is a shallow rooted crop. A healthy crop of potato removes about 25-30 kg P2O5/ha from soil indicating that potato need for Phosphorus is much higher than most of cereals. Therefore, this book is designed for educating the optimize phosphorus requirement of potato through organic and inorganic sources.