There is a growing body of evidence implicating the neurotrophin brain-derived neurotrophic factor (BDNF) in the pathogenesis of schizophrenia. As circulating BDNF levels may reflect the BDNF levels in the brain, we assessed serum BDNF in 40 institutionalized schizophrenic patients and 20 healthy controls. Serum BNDF levels were significantly increased in schizophrenic patients when compared to control subjects (p<0.001). Interestingly, serum BDNF correlated positively with the clinical scores at the negative subscale of the positive and negative syndrome scale (PANSS) (r=0.41; p<0.01). Our results confirm the emergent literature on the involvement of BDNF in schizophrenia.