Fermented ginseng (FG) is an ethanol extract of ginseng radix processed with $eta$-galactosidase. It was hypothesized that FG may exert anti-hyperlipidemic and anti-diabetic activities through modulating AMP-activated protein kinase (AMPK) in HepG2 human hepatoma cells. In this study, we showed that AMPK phosphorylation was stimulated by FG. These effects were abolished by pretreatment with an AMPK inhibitor, compound C. In addition, FG regulated the expression of genes associated with lipogenesis and lipolysis, thus causing suppression of hepatic triglyceride accumulation. In vivo study using db/db mice, FG reduced fasting plasma glucose, HbAlc, and insulin resistance index, when compared to diabetic control. FG also increased the phospho-AMPK and glucose transporter 4 (GLUT4) expressions in liver and skeletal muscle, respectively. In liver, expressions of lipogenic gene were decreased whereas expressions of lipolytic genes were induced, when compared to diabetic control. Taken together, we may suggest that FG ameliorates hyperglycemia and hyperlipidemia through activation of AMPK and could be developed as a health functional food or therapeutic agent for type 2 diabetic patients.