Synthetic chemicals used in plant disease control and synthetic antioxidants have undesirable effects, leading to interest in plant-based alternatives. This study focused on Melia azedarach, a medicinal plant. The aims were (i) to investigate the chemical composition of essential oils from flowers and fruits of M. azedarach cultivated in Kashan, central Iran, (ii) to assess the antioxidant activity of methanol extracts using 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical assay and β-carotene/linoleic acid bleaching assay, and to determine total phenolic content. The chemical composition of flower and fruit essential oils is presented in Table 1. DPPH assay showed IC50 values: green fruit (265.12±12.90 μg/mL), flower (321.14±7.8 μg/mL), ripe fruit (1584.87±0.05 μg/mL), and positive control BHT (19.72±0.80 μg/mL). Total phenolic content was flower (24.44±0.3 μg gallic acid equivalents/mg dry sample), green fruit (20.90±0.05), and ripe fruit (3.37±1.04). Lipid peroxidation inhibition was evaluated via β-carotene/linoleic acid bleaching test (results in Fig. 1). This is the first report of in vitro antioxidant activity of extracts from different parts of M. azedarach. Among the tested methods, the highest activity was observed in the β-carotene-linoleic acid test for the flower methanol extract, which may serve as a potential natural antioxidant source for the food industry.