Electrochemical cobalt-catalyzed C-H functionalizations were achieved in terms of C-H oxygenation under mild conditions at 23 degrees C. The robust electrochemical C-H functionalization was characterized by ample substrate scope, whereas mechanistic studies provided support for a facile C-H cleavage. The electrochemical cobalt-catalyzed C-H oxygenation proved viable on arenes and alkenes with excellent levels of positional and diastereo-selectivity, avoiding the use of stoichiometric silver(I) oxidants under ambient conditions.