Kynurenine 3-monooxygenase (KMO; EC 1.14.13.9) is an enzyme in the eukaryotic tryptophan catabolic pathway (i.e. kynurenine pathway (KP)). KMO is a FAD-dependent monooxygenase, and is located in the outer mitochondrial membrane where it converts L-kynurenine to 3-hydroxykynurenine (3-HK). Inhibition of KMO has shown to cause amelioration of Huntington’s disease-relevant phenotypes in yeast, fruit fly, and mouse models, as well as a mouse model of Alzheimer’s disease. The effect of KMO inhibition is a shift in the KP toward kynurenine aminotransferase (KAT; EC 2.6.1.7) mediated enhanced kynurenic acid (KYNA) production which, in turn, may cause reduced neuronal vulnerability. Indeed, the most widely used KMO inhibitor, Ro 61-8048 (Axon 2139), is beneficial in rodent models of brain ischemia, cerebral malaria, and trypanosomiasis, and in a primate model of Levodopa-induced dyskinesias[1]. Alterations in the levels of kynurenine pathway metabolites have been linked to the pathogenesis of a spectrum of brain disorders, as well as cancer, and several peripheral inflammatory conditions[2].