tThe unspecific peroxygenase from the fungus Agrocybe aegerita (AaeUPO) is an up-and-coming biocat-alyst that is able to perform specific oxyfunctionalizations of various substrates. Due to inactivationat excess concentrations of its co-substrate H2O2, AaeUPO’s technical application is still limited. Thisstudy aims to promote catalyst efficiency via electrochemical in situ supply of H2O2, using an evolvedvariant of AaeUPO on the example of ethylbenzene hydroxylation. Total turnover numbers of up to400,000 molproductmolAaeUPO−1and space-time-yields of up to 25 g L−1d−1were achieved in the electro-enzymatic system. These numbers are in the upper range of published data. The presented system standsout by its very high atom economy. Thus, combining electrochemistry and biocatalysis is one step closertowards the first application of peroxygenases in an industrial process.