The Mango is an important tropical fruit tree with very huge vegetative growth. Their botanical name is Magiferra indica belongs to the family Anacardiaceae. Ripe mangoes are the more popular and delicious fruit of the Orient and have been described as a king of all fruits. Also, it is greatly preferred and required with great demand especially superior cultivars. Two experiments were conducted to study the effect of different sources of N fertilizers and different concentrations of either Uncoated urea (Fast release chemical fertilizer or Coated urea (Slowrelease fertilizer) on the growth and development of Keitt Mango transplants. Application of different nitrogen fertilizers in the form of Nitrobin+ urea (combination of bio and chemical fertilizer) followed by Coated urea (slow-release fertilizer) enhanced improvement in most parameters of plant dimensions, vegetative growth, plant fresh weight, fresh & dry root weight, Maximized leaf N level and both leaf P &K levels, Chlorophyll A& B, and Carotene parameters. Also, Coated urea (slow-release fertilizer) was superior to Uncoated urea (Fast release fertilizer) in maximizing most parameters under study. Furthermore, the 
superiority of using 10gm/L concentration from Coated Urea over 15 gm/L increases the most parameters under study.