Evidence suggests that the adenosine A2a receptor (A2aAR) may be implicated in the pathogenesis of mood disorders. We tested the hypothesis that the A2aAR 1976C>T genetic variant confers susceptibility to mood disorders by comparing 192 mood disorder patients and 216 normal controls. The distribution of the A2aAR genotypes and alleles did not differ significantly comparing the two groups, suggesting that it is unlikely that the A2aAR 1976C>T polymorphism plays a major role in the development of mood disorders.