Kinetics of electrochemical oxidations of ferrocene (Fc) and 2- and 5-(ferrocenylcarboxy)dodecyltrimethylammonium nitrates (2-Fc and 5-Fc, respectively) were studied to yield information about the electrode-fluid interface in a bicontinuous microemulsion. Apparent standard heterogeneous electron-transfer rate constants (k degrees’) for Fc, 2-Fc, and 5-Fc at glassy carbon electrodes were similar in homogeneous acetonitrile, as found earlier in DMSO. In a bicontinuous microemulsion of n-tetradecane, water, pentanol, and cetyltrimethylammonium chloride (CTAC), electron-transfer rates for Fc, 2-Fc, and 5-Fc were an order of magnitude smaller than in acetonitrile. Ferrocene had a k degrees ’twice as large as 2-Fc and 5-Fc in the CTAC microemulsion. Small differences in rates of 2-Fc and 5-Fc cannot be explained by a head down-tail up orientation at the time of electron transfer, as proposed to explain kinetics in micellar CTAB solutions. Results suggest the possibility of increased disorder and mobility in the electrode-fluid interface in the CTAC microemulsion compared to micellar CTAB solutions.