We investigated the susceptibility of the dinucleotide polymorphism A0 in the tau gene to amyotrophic lateral sclerosis (ALS). In 416 unrelated patients with ALS and 242 control subjects the A0/A0 genotype was not associated with the pooled sample of ALS cases. Subgroup analysis revealed that in sporadic ALS the A0 polymorphism was significantly overrepresented. There was no association of the A0/A0 genotype with the age and site of disease onset or the presence of dementia. The studied tau genotype may contribute to the multifactorial genetic background of ALS.