The mosquitocidal and repellent activity of the green tea, Camellia sinensis leaves extract against Culex pipiens was evaluated. Toxicity of this extract increased with increasing the concentration, the recorded LC₅₀ was 540 and 600 ppm for larvae and pupae, respectively. The extract showed a significant prolongation in both larval and pupal duration. In addition, it caused a great effect in pupation and adult emergence percent. The green tea, Camellia sinensis leaves extract was found to have a remarkable malformative effect on both larvae and pupae. The green tea leaves extract was effective in exhibiting antifeedant and repellent activity against Culex pipiens mosquitoes; it gave the highest protection (100%) from the bites of starved females at the dose of 6 mg/cm². The major bioactive chemical constituents in green tea leaves extract were identified using HPLC and FT-IR analysis. These results suggest that the leaves extract of green tea, Camellia sinensis can be considered as alternative mosquitocide and repellent agent.