The RNA binding protein RBFOX2 is linked to heart and skeletal muscle diseases; yet, RBFOX2-regulated RNA networks have not been systematically identified.Although RBFOX2 has a well-known function in alternative splicing (AS), it is unclear whether RBFOX2 has other roles in RNA metabolism that affect gene expression and function. Utilizing state of the art techniques Poly(A)-ClickSeq (PAC-seq) and nanopore cDNA sequencing, we revealed a new role for RBFOX2 in fine tuning alternative polyadenylation (APA) of pre-mRNAs in myoblasts. We found that depletion of RBFOX2 altered expression of mitochondrial genes. We identified the mitochondrial gene Slc25a4 gene that transports ATP/ADP across inner mitochondrial membrane as a target of RBFOX2. Dissecting how RBFOX2 affects Slc25a4 APA uncovered that RBFOX2 binding motifs near the distal polyadenylation site (PAS) are critical for expression of Slc25a4. Consistent with changes in expression of mitochondrial genes, loss of RBFOX2 altered mitochondrial membrane potential and induced mitochondrial swelling. Our results unveiled a novel role for RBFOX2 in maintaining APA decisions and expression of mitochondrial genes in myoblasts relevant to heart diseases. Keywords: alternative polyadenylation/mitochondria/nanopore sequencing/ poly(A) sequencing/RBFOX2 Non-standard Abbreviations and Acronyms: AS alternative splicing PAC-seq poly(A)-ClickSeq APA alternative polyadenylation KD knock down 3´UTR 3´untranslated region PAS poly(A)-site PAC poly(A)-cluster DPAC differential-poly(A)-clustering dPAS distal poly(A)-site pPAS proximal poly(A)-site ANT1 (Slc25a4) ATP/ADP translocator (mitochondrial) MFN1 Mitofusin