The present invention provides a composition comprising one or more deoxyribonucleosides for use in the treatment of a mitochondrial DNA depletion and/or multiple deletions syndrome provided that the syndrome is not caused by a defect in the deoxyribonucleoside triphosphate (dNTP) metabolism. With the use of the invention there is a recovery in mitochondrial DNA levels independently from the severity of the patient's disease, which confers a great therapeutic value to the invention.
