Our understanding of how global changes in cellular metabolism contribute to human kidney disease remains incompletely understood. Here we show that nicotinamide adenine dinucleotide (NAD⁺) deficiency drives mitochondrial dysfunction causing inflammation and kidney disease development. Using unbiased global metabolomics in healthy and diseased human kidneys, we identify NAD⁺ deficiency as a disease signature. Furthermore using models of cisplatin- or ischaemia-reperfusion induced kidney injury in male mice we observed NAD⁺ depletion Supplemental nicotinamide riboside or nicotinamide mononucleotide restores NAD⁺ levels and improved kidney function. We find that cisplatin exposure causes cytosolic leakage of mitochondrial RNA (mtRNA) and activation of the cytosolic pattern recognition receptor retinoic acid-inducible gene I (RIG-I), both of which can be ameliorated by restoring NAD⁺. Male mice with RIG-I knock-out (KO) are protected from cisplatin-induced kidney disease. In summary, we demonstrate that the cytosolic release of mtRNA and RIG-I activation is an NAD⁺-sensitive mechanism contributing to kidney disease.