A cyclic voltammogram for reduction of 1-adamantanecarbonyl chloride at a glassy carbon or hanging mercury drop electrode in acetonitrile containing 0.10M tetraethylammonium perchlorate displays two irreversible cathodic waves; the first wave is attributable to reductive cleavage of the acyl chloride and the second wave is caused by reduction of 1-adamantanecarboxaldehyde. Controlled-potential electrolyses of 1-adamantanecarbonyl chloride at potentials corresponding to the first wave yield 1-adamantanecarboxaldehyde in yields that approach 100%. On the basis of the coulometric n value of one, and because 1-adamantanecarbox(aldehyde-d) is formed nearly quantitatively when the starting material is electrolyzed in acetonitrile-d(3) (a hydrogen atom donor), we conclude that 1-adamantanecarbonyl chloride undergoes one-electron reduction to an acyl radical, which accepts a hydrogen (deuterium) atom from the solvent to afford the aldehyde.