A strong association of the G196A polymorphism of the brain-derived neurotrophic factor (BDNF) gene with obsessive-compulsive disorder (OCD) has been reported. Patients with Gilles de la Tourette's syndrome (GTS) often develop OCD as well, suggesting a shared genetic susceptibility for OCD and GTS. We investigated whether BNDF is associated not only with OCD but also with GTS. The G196A polymorphism of the BNDF gene was genotyped in 88 GTS trios. The extended transmission/disequilibrium test was applied. The transmission rates for both alleles did not differ from the expected transmission rates. This finding suggests that GTS and OCD may have distinct genetic risk factors.