Dietary anthocyanins are widely distributed in fruits, vegetables and red wines, and there are several reports mentioning their beneficial effects. Previously we reported that cyanidin-3-glucoside (Cy3G) induced endothelial nitric oxide synthase (eNOS) expression and nitric oxide (NO) production in bovine vascular endothelial cells. In the present study, we show that Cy3G regulates phosphorylation of eNOS and Akt, affects the interaction between eNOS and soluble guanylyl cyclase, and increases cyclic guanosine monophosphate (cGMP) production. Our results suggest that Cy3G enhances vascular eNOS activity, and may help to improve vascular endothelial function.