Bendavia is a mitochondria-targeting peptide currently being tested in the EMBRACE-STEMI trial for reducing injury during acute coronary syndromes. We previously showed that the cardioprotective effects of Bendavia involved improving cardiolipin-dependent mitochondrial membrane fluidity. As membrane fluidity influences the ability of proteins to assemble, we hypothesized that a consequence of augmented membrane fluidity would be higher expression of mitochondrial respiratory supercomplexes. Rat hearts (n=42) were subjected to ischemia-reperfusion (I/R) with or without 1nM Bendavia perfusion beginning at the onset of reperfusion. Left ventricular tissue was split into one of two study arms: 1. Supercomplex expression using blue-native gel electrophoresis (BN-PAGE), or 2. High-resolution respirometry using permeabilized ventricular fibers. For BN-PAGE studies, respiratory supercomplex bands were decreased with I/R, and restored with Bendavia (see figure). High-resolution respirometry studies indicated suppressed Complex I-dependent respiration after I/R (208±19 v 42±9 pmol O2/mg*s in control v I/R, respectively; P<0.05). Complex II-dependent respiration was also lower (753±41 v 168±13 pmol/mg*s in control versus I/R; P<0.05). Perfusion with Bendavia during reperfusion significantly increased Complexes I- (100±13pmol O2/mg*s) and II-dependent (334±63 pmol O2/mg*s) respiration (P<0.05 versus untreated IR for both). Taken together, these data suggest that Bendavia’s protective mechanism of action involves preserving supercomplex-dependent mitochondrial function during cardiac reperfusion.