Significance Neurons depend on oxidative phosphorylation for survival, whereas astrocytes do not. Mitochondrial respiratory chain (MRC) complexes can be organized in higher structures called supercomplexes, which dictate MRC electron flux and energy efficiency. Whether the specific metabolic shapes of neurons and astrocytes are determined by the specific organization of MRC complexes is unknown. Here, we found that, in astrocytes, most complex I is free, resulting in poor mitochondrial respiration but high reactive oxygen species (ROS) production. In contrast, neurons show complex I to be mostly embedded into supercomplexes, thus resulting in high mitochondrial respiration and low ROS production. Thus, MRC organization dictates different bioenergetics preferences of neurons and astrocytes impacting on ROS production, possibly playing a role in neurodegenerative diseases.