Brain-derived neurotrophic factor (BDNF), is a member of neurotrophinfamily having roles in survival, growth and function of neurons in the central and peripheral nervous system. BDNF mRNA and protein levels have been identified in the cerebellum, hippocampus, bulbus olfactorius, spinal cord, thalamus, prefrontal cerebral cortex, hypothalamus, amygdala, regions of the projections of the olfactory system, striatum and superior colliculus. Although the early BDNF expression studies have demonstrated that this molecule were related with neurons, while in subsequent studies theBDNF synthesis have been determined in non-neuronal cells of central nervous system, peripheral vascular endothelial cells, lymphocytes, platelets, leukocytes, monocytes, T and B lymphocytes. Also, BDNF mRNA expression has been reported in heart, lung, kidney, spleen and urinary bladder cells. The expression and concentration of BDNF varies in physiological events and pathological situations. BDNF serves mainly to the development and refreshment of neurons in the central nervous system in addition to contributing to be structurally healthy of important nerve pathways and to the continuity of their performance. Because of the importance of BDNF to the neuronal survival and function in nervous system, applications of this neurotrophin in treatment of neurodegenerative diseases has gained importance and acceleration. The purpose of this review is to provide information about the structure, synthesis, functions and therapeutic use of BDNF.