This study evaluated the influence of in ovo injection (IOI) of various levels of L-arginine (LA) on performance and bone minerals in hatched chickens. A total of 500 fertile eggs were randomly distributed into 5 groups (100 eggs for each group). Three groups were injected with 20, 40, or 60 mg LA per egg dissolved in 0.5 ml normal saline. Rests two groups were used as un-injected control and injected control (injected with 0.5 ml normal saline). The hatched chickens from each group were randomly assigned to 4 replications of 12 chickens and reared under standard condition. A quadratic increase (P=0.007) in hatchability percentage and linear increase (P≤0.008) in body weight (BW), alkaline phosphatase (ALP) activity and tibial contents of phosphorous (P) and copper (Cu) was observed with increasing levels of LA in hatched chickens. In addition, Ca content of tibia increased (Linear: 0.001; Quadratic: 0.003) with increasing levels of LA. Body weight gain (BWG), feed intake (FI) and the activities of ALP and aspartate amino transferase (AST) linearly increased (P≤0.041) with increasing levels of LA at 21 day of age. The results indicated that LA at the level of 20 or 40 mg per egg can accelerate broiler performance and bone minerals.