Abstract A study has been made of the redox reactions occurring on a bilayer lipid membrane (BLM) formed from egg lecithin with mitochondrial NADH dehydrogenase coenzymes. It was shown that in a system of successive NADH-FMN-Q 6-K 3[Fe(CN) 6] reactions occurring when NADH and FMN are on one side of the membrane and ferricyanide on the opposite one, there arises a potential due to transmembrane electron transfer which is removed by the uncoupler (protonophore). A side reaction was identified, in which the membrane lipids are oxidized. This reaction is accompanied by the transfer of protons to the layer adjacent to BLM (unstirred layer), which is catalyzed by flavin mononucleotide. In this case, the uncoupler protonophore stimulates an increase in potential. Reactions on BLM have been studied, which involve two concurrent processes: the oxidation of NADH and the oxidation of lipids.