During autophagy, mitochondria elongate, are spared from degradation, and sustain cell viability. Mitochondrial morphology determines the cellular response to macroautophagy. When autophagy is triggered, mitochondria elongate in vitro and in vivo. Starvation increases cellular cAMP levels, activating protein kinase A (PKA), which phosphorylates the pro-fission dynamin-related protein 1 (DRP1), retaining it in the cytoplasm and promoting mitochondrial fusion. Elongated mitochondria are spared from autophagic degradation, have more cristae, increased ATP synthase dimerization and activity, and maintain ATP production. Blocking elongation leads to ATP consumption and starvation-induced death. Mitochondrial elongation is regulated by PKA-mediated inhibition of DRP1. Elongated mitochondria are protected from autophagic elimination, maintain ATP levels, and support cell survival during starvation. Mitochondrial elongation during autophagy is critical for cell viability, as it prevents mitochondrial dysfunction and cell death. The study highlights the role of mitochondrial morphology in autophagy and its impact on cellular survival.During autophagy, mitochondria elongate, are spared from degradation, and sustain cell viability. Mitochondrial morphology determines the cellular response to macroautophagy. When autophagy is triggered, mitochondria elongate in vitro and in vivo. Starvation increases cellular cAMP levels, activating protein kinase A (PKA), which phosphorylates the pro-fission dynamin-related protein 1 (DRP1), retaining it in the cytoplasm and promoting mitochondrial fusion. Elongated mitochondria are spared from autophagic degradation, have more cristae, increased ATP synthase dimerization and activity, and maintain ATP production. Blocking elongation leads to ATP consumption and starvation-induced death. Mitochondrial elongation is regulated by PKA-mediated inhibition of DRP1. Elongated mitochondria are protected from autophagic elimination, maintain ATP levels, and support cell survival during starvation. Mitochondrial elongation during autophagy is critical for cell viability, as it prevents mitochondrial dysfunction and cell death. The study highlights the role of mitochondrial morphology in autophagy and its impact on cellular survival.