Growth hormone (GH) secretion decreases in ageing and in neurodegenerative diseases. The plasma level of the hormone declines in aged individuals and in victims of CNS injury. Exogenous GH is neuroprotective in animal models of CNS trauma. The GH replacement therapy improves psychological capabilities in young and in adult growth hormone deficient (GHD) patients suggesting that the hormone has profound beneficial effects on the CNS function. The mechanism by which GH reaches its presumable brain targets is, however, not fully clarified. Clinical studies suggest that the hormone reaches its responsive areas in the brain after passing the blood-brain-barrier (BBB). On the other hand, animal studies show that GH under normal conditions does not cross the CNS barriers. However, the hormone enters into the fluid microenvironments of the CNS and influences the brain or spinal cord neurons through leaky barriers in several disease conditions. Intracerebroventricular infusion of GH reduces neuronal loss in CNS injury and topical application of the hormone on the traumatised cord induces neuroprotection. This review summarizes basic aspects of GH permeability across the BBB or the blood-spinal cord barrier (BSCB) and the mechanisms of GH action on its CNS targets as well as its neuroprotective potential is described.