Complex I of the mitochondrial respiratory chain consists of 44 subunits encoded by both mitochondrial and genomic DNA giving it a unique dual genetic control. NDUFA13 is a known nuclear encoded subunit of complex I but it is has also been reported to be a negative regulator of the Signal Transducer and Activator of Transcription 3 (STAT3). STAT3 is a nuclear transcription factor that is also present in mitochondria and may interact with the mitochondrial apoptosis machinery. However, the molecular mechanisms of how NDUFA13 fulfils both roles remain elusive. Diseases that are associated with NDUFA13 loss of function include various cancers as well as Electron Transport Chain and metabolic pathways disorders. Earlier attempts by the research community to create NDUFA13 knock-out mice failed and revealed that NDUFA13 disruption is embryonically lethal. Therefore a novel knock-out cell line would harbour potential to address remaining questions regarding the function of NDUFA13. By applying the new genome editing technology of transcription activator-like effector nucleases (TALEN) technique we were successfully able to create a novel cell line harbouring a gene disruption for NDUFA13. Extensive biochemical analysis of this NDUFA13 knock-out cell line will be presented.