In this investigate conducted during period of 2008 to 2011 to study the effect of  NPK fertilizer on annual increment rate for growth of Swietenia mahagoni, Fam. Meliaceae. The trees were at the age seven years old, which have been planted at a distance of 3mx3m in new reclaimed land, north west of Cairo, Egypt, at the Experimental Farm of Aly Moubarak Hort. Res. Inst. Agric. Res. Center (ARC).  They were fertilized with ammonium sulphate (15.5% N) at the rates of N₁ = 0.0, N₂ = 51.61 and N₃ = 103.22 g, superphosphate (40-46% P₂O₅) at the rates of P₁ = 0.0, P₂ = 64.51 and P₃ = 129.03 g and potassium sulphate (50% K₂O) at the rates of K₁ = 0.0, K₂ = 16.00 and K₃ = 32.00 g all per tree, which they were 27 treatments. The best treatments which were more effective in annual rate increment for height (ARIH) were K₁N₂P₃ and K₂N₂P₁ (88.333 and 83.333 cm) in the first year and K₃N₁P₃ (83.333 cm) in the second year of fertilization. The treatment of K₃N₂P₂ caused the high value of annual rate increment for diameter at breast height (ARIDBH) which was (3.040 cm) and high value of annual rate increment for Basal area (ARIBA) which was(56.970 cm²)  in the first year of fertilization, while, in the second one K₂N₃P₃ treatment produced high value of BAAI (56.843 cm²). However, in the third year of fertilization there was no significant effect of NPK fertilizers on the previous measurements, in addition to in many treatments fertilization  lead to an adverse effect on these measurements.