We have analysed the MAOA-uVNTR polymorphism in the promoter region of the X-chromosomal monoamine oxidase A (MAOA) gene. The first aim was to examine the association between the MAOA genotype and the alcoholic phenotype. In the second part of the paper we have analysed the association of the MAOA genotype with impulsive and aggressive behaviour. Genotypes with 3 or 5-repeat alleles (MAOA-L-genotype) were reported to be associated with impulsive and aggressive traits.