A gold microdisk has been used to determine the diffusion coefficient (D) for dimethylamine borane (DMAB) in concentrated alkaline solution. Two steady-state oxidation waves were resolved through the use of microelectrodes. Using the D value determined, the coulomb number for both oxidation waves was shown to be 3. The first wave may be further resolved in dilute solutions revealing three one-electron steps. The concentration range wherein the maximum coulombic efficiency for DMAB oxidation on gold may be achieved is demonstrated. An oxidation pathway with a variable coulomb number is suggested. (C) 2005 The Electrochemical Society.