Authors investigated effects of the Val66Met polymorphism of the brain-derived neurotrophic factor (BDNF) gene and level of trait anxiety on attention in 90 patients with schizophrenia or schizoaffective psychosis. Attention was assessed using auditory event-related brain potentials (ERPs) and neuropsychological testing. There was a significant effect of the BDNF genotype, but not anxiety, on performance on the neuropsychological test and on the P300 amplitude in frontal and temporal leads. Carriers of a Met allele performed worse and showed lower P300 amplitude during the attention task than those with the ValVal genotype. The interaction effect of the genotype and anxiety was observed for non-target N100 amplitude in central and parietal leads. This effect depended on the level of anxiety: the interaction was significant only in the group with the lower level of anxiety. In this group, a Met allele was associated with the lower N100 amplitude. It was suggested that BDNF genotype does not contribute to brain electrical activity at the first stage of stimulus recognition (N100) because highly anxious people tend to be more attentive, regardless of genotype, due to the fear about their ability to cope with the task requirements.