Chemotherapy treatment can cause a permanent loss of female fertility and premature menopause, through the destruction of ovarian follicles. Options to preserve fertility in female patients are presently limited. The aim is to investigate a novel pharmacological approach to restore ovarian functions during and after chemotherapy treatment by altering levels of the metabolite nicotinamide adenine dinucleotide (NAD+), a critically important substrate to the sirtuins, a class of NAD+ dependent deacylase proteins thought to play a key role in biological ageing, and to poly-ADP ribose polymerase (PARP) enzymes, which mediate the cellular response to DNA damage. We hypothesised that increasing NAD+ availability might lead to protection against chemotherapy induced ovarian damage, which we investigated through the administration of the metabolic NAD+ precursor nicotinamide mononucleotide (NMN), in combination with chemotherapy treatment using either doxorubicin or cis-platin, two unrelated chemotherapy drugs. Strikingly, while chemotherapy resulted in drastic reductions in the number of primordial follicles, mature oocytes, and the numbers of pups born per litter, NMN co-treatment completely rescued these parameters. To further prove this mechanism, we obtained mice which over-expressed the NAD+ biosynthetic enzymes NMNAT1 or NMNAT3, which are localised to the nucleus and mitochondria, respectively. NMNAT1-Tg animals were protected against a loss of oocytes during chemotherapy treatment, whereas NMNAT3-Tg mice were not, suggesting that nuclear NAD+ is most important to this mechanism. Next, we investigated the effects of administering NMN four weeks after chemotherapy treatment, and observed a partial restoration of the number of primordial follicles, and mature oocytes, in NMN treated animals. This latter finding has important implications for the possibility of ovarian rejuvenation, via oogonial stem cells. Together, these findings have application not just in the clinical treatment of chemotherapy induced infertility, but in our understanding of ovarian ageing and damage, in particular, the possibility of ovarian renewal.