Objectives We investigated anti-obesity effects of essential oils extracted from Cnidii Rhizoma (CR) in immature adipocytes to magnify it’s clinical therapeutic usage. Methods Essential oil of CR was extracted with ethyl acetate or petroleum ether and through steam distillation, respectively. Oil red-O staining for monitoring its inhibition effect on adipogenesis and differentiation in murine 3T3-L1 adipocytes and 3-(4,5-methylthiazol- 2-yl)-2,5-diphenyletetra zolium bromide (MTT) assay for cell safety were done. Also phospho- adenosine monophosphate (AMP)-activted protein kinase (P-AMPK), AMP-activated protein kinase, phospho-acetyl-CoA carboxylase (P-ACC), acetyl-CoA carboxylase, peroxisome proliferator-activated receptor-α (PPAR-α), peroxisome proliferator-activated receptor- γ (PPAR-γ) and CCAAT/enhancer binding protein α (C/EBP-α) expressions as obesity-related factors were measured by western blot analysis. Results Protein expressions of P-AMPK, P-ACC and PPAR-α were increased in essential oils-treated adipocytes compared to those of control group, respectively. Furthermore, protein expressions of PPAR-γ and C/EBP-α were decreased in essential oils-treated adipocytes compared to those of control group, respectively. Conclusions These results demonstrate that essential oils of CR inhibit adipogenesis and differentiation. Also they promote the oxidation of fatty acids in adipocytes. Thus, results suggest that essential oils of CR could be used as a valuable material for anti-obesity therapeutics via control of lipid metabolism. (J Korean Med Rehabil 2018;28(3):13-25)