Rickets is a severe vitamin D deficient disorder mostly of developing countries due to the least exposure to sunlight and poor nutrition. Rickets causes inappropriate absorption of phosphorus and calcium. It retards growth; alters phosphorus, calcium, and vitamin D metabolism and causes the bony manifestation of the patient. We describe the clinical course severe vitamin D deficiency in a boy of three years with cold and dry cough sweats on the forehead at night and can’t walk and stand. Multi-disciplinary physical, laboratory, and clinical analysis; the child was diagnosed as nutritional rickets with fever and respiratory infection. Treatment with proper exposure to sunlight vitamin supplements and adequate nutrition is directed. Rickets is a worldwide public health problem that arises due to vitamin D and calcium deficiency found more in children than adults. Early diagnosis of rickets in humans provides the optimal and proper treatment for saving a patient’s life.Keywords: Nutrition, rickets, vitamin D, public health.Citation: Imran, Khan, W., Mehmood, S.A., Ahmed, S., Khan, I., 2020. Nutritional Rickets in Three Years Old Boy: A Case Report. PSM Biol. Res., 5(3): 106-109.