The orientation of adsorbed aliphatic alcohols on mercury electrode surface is discussed on the basis of literature data concerning steric factors of electrochemical reactions inhibited by these alcohols and on quantum chemical calculations using the MOPAC program. Steric factors were evaluated from dependences of rate constants of electrochemical reactions of several model systems on alcohol concentration at total surface coverage. Theoretical calculations were made for a single alcohol molecule interacting with a 28-atomic mercury cluster. These two sets of data point to a vertical orientation of adsorbed alcohol molecules, even at incomplete coverage of the electrode surface.