Ethanol, 2.4 g/kg, or saline was given intraperitoneally to mice separately or 3 h after α-methyltyrosine, a tyrosine hydroxylase inhibitor. Some animals also received l-Dopa in various doses 2 h before ethanol or saline. All animals received an inhibitor of peripheral Dopa decarboxylase 30 min before l-Dopa. Immediately after the last injection the locomotor activity was recorded every 5 min for 1 h. The ethanol-induced stimulation of locomotor activity was suppressed by α-methyltyrosine. This suppression was partially reversed by l-Dopa. The reversal appeared to be optimal at a low dose of l-Dopa, 5–20 mg/kg, which by itself did not appear to influence the locomotor activity. These results support the view that central catecholamines are involved in the stimulatory action of ethanol on locomotor activity.