Abstract: This study ‘in vivo’ was applied on rats “Rattus norvegicus” to determine the acute toxicity of water extracts of Azadirachta indica leaves and seeds during 48 hours and the 50% lethal dose (LD50) values were calculated. Different doses of A. indica water extracts of leaves and seeds were injected to the rats (Rattus norvegicus) and the percentage of death was recorded during 48 hours. The present study, found that the percentage of death in all treated rats with A. indica leaves and seeds water extracts were increased by doses increased (R2 = 0.9). Rats injected with higher doses of water extract of A. indica leaves (0.1 and 0.092 g mL-1) and seeds (0.2 g mL-1) showed 100% death. The LD50 of water extract of A. indica leaves and seeds were 6.2, 9.4 mL kg-1, respectively. Based on these results, it may be concluded that doses of water extract of A. indica leaves and seeds injected to rats showed significant acute toxicity.