Attention deficit hyperactivity disorder (ADHD) is a multifactorial disorder with significant genetic contribution. Dopamine genes have been the initial candidates based on the site of the action of the psychostimulant drugs. The other genes from neurotransmitter and immune system are in focus too. We have investigated whether there is an association between ADHD and polymorphisms of 13 candidate genes: DAT1, DRD2, COMT, MAOB, ACE, ANG, CCR5, BDNF, MU, IL-2, IL-6, TNF-alpha, and M235T. The aim of our case-control study was to determine whether the ADHD boys (118) have different genotype and alelic frequencies of examined polymorphisms of the above mentioned genes compared to controls (153). No significant differences were found between groups of boys in allelic and genotype frequencies of COMT, MAOB, ACE, ANG, CCR5, BDNF, MU, IL-2, IL-6, TNF-alpha and M235T genes (p < 0.05). For DAT1, the statistical analysis using Fisher exact test did not confirme the association of the previously possitive investigated 10-repeat allele or 10/10 genotype of DAT1 gene (p = 0.531). For DRD2, ADHD probands were more likely than controls to have the A1 allele and genotype A1A1 (p = 0.0013). Our results showed that ADHD in Czech children population is associated with TaqI A polymorphism of DRD2 gene. The presence of DRD2 A1 allele increases the risk of ADHD.