The purpose of this study was to evaluate the effects of sub-chronic exposure to deltamethrin in lower doses on the acquisition of a two-way avoidance task and the levels of amino acid neurotransmitters in hippocampus of mice measured using shuttle-box and LC-MS/MS system. Deltamethrin was given to mice respectively at doses of 0.46, 0.92, 1.80 mg/kg BW daily for 60 days by gavage. Deltamethrin was found to decrease the number of avoidance responses, increase response latency, and increase glutamate levels in the 0.92 and 1.80 mg/kg BW-dose group. As revealed by electron microscopy, in 0.92 and 1.8 mg/kg-dose group mice, morphology of cells were changed and degeneration and necrosis morphological characteristics obviously were appeared. Collectively, results from this study suggest that deltamethrin may have cumulative effects in mice following repeated dosing of deltamethrin using moderately effective doses, beside Na⁺ and Ca²⁺ channels as well as Na⁺ and Ca²⁺-dependent glutamate release, may be involved with neurotoxic action of deltamethrin.