For the last few decades, there has been extensive research and supporting evidence for the role of monoamine oxidase (MAO) activity and its' possible manipulation in the pathophysiology of neurodegenerative disorders. Although, the role of dopaminergic, noradrenergic and serotonergic systems in central nervous system (CNS) and neurodegenerative diseases have been mostly demonstrated, the intrinsic mechanisms in these systems with relation to other molecules in CNS have received less attention. A more recently discovered molecule, nitric oxide (NO) has also gained attraction in a number of physiological and pathological states. Much of this attraction is due to the role of NO as a neurotransmitter/neuromodulator in the CNS. This review will describe our current state of knowledge about the established biochemical mechanisms of MAO and NO, with particular emphasis on aging and neurodegenerative disorders. Possible intrinsic mechanisms which are likely to be of crucial importance will also be discussed and a link in between will be proposed based on the evidence derived from recent basic and clinical research.