In this study, the Chemical composition and bio-efficacy of essential oils (EOs) from Anethum graveolens, Thymus vulgaris, and Myristica fragrans were assessed. Seventeen, forty-five and twenty-nine compounds were identified in A. graveolens, T. vulgaris, and M. fragrans, respectively by GC-MS analysis. Dillapiole (44.01 %), D-Limonene (19.47 %), and carvotanacetone (13.03 %) in A. graveolen EO; estragole (15.30 %), γ-terpinene (14.49 %), and thymol (10.80 %) in T. vulgaris EO; safrole (14.93 %), α-terpinolene (14.65 %), and elemicin (14.62 %), in M. fragrans EO, were the main compounds. The bio-efficacy of these essential oils was tested against adults of major insect pests namely Callosobruchus maculatus using fumigant toxicity and biological parameters. Results revealed that the A. graveolens EO was the most toxic oil against C. maculatus adults with LC50 and LC90 values of 10.1 and 25.5 μl/l air, respectively after exposure for 24 h. EO of A. graveolens killed C. maculatus adults faster than T. vulgaris and M. fragrans. A. graveolens and T. vulgaris showed the highest effect on biological parameters of oviposition. This study suggests that EO from A. graveolens could be potentially using in IPM programs for suppressing this pest in infesting cowpea seeds.