Background: Mood disorders, consisting of unipolar and bipolar depression, are complex diseases characterized by depressed mood and anhedonia. These core symptoms are accompanied in a varying manner by anxiety, several neurovegetative symptoms and cognitive impairment. Mood disorders are characterized by decreases in neurogenesis, alteration in synaptic structure and synaptic transmission, all of them regulated by BDNF, a neurotrophin that performs multiple functions in the adult central nervous system. Many evidences show that BDNF is critically decreased in mood disorders and plays an essential role in most anti-depressant treatments. In turn, the transcription factor NF-kB has recently emerged as an important player in the pathophysiology of depression, with roles in neurogenesis, synaptic transmission and plasticity. Keywords: BDNF, NF-κB, mood disorders, neurogenesis, plasticity, anhedonia.