The aim of the present study was to investigate whether there is an association between the (TCAT)(n) repeat polymorphism in the tyrosine hydroxylase (TH) gene and personality. The (TCAT)(n) repeat polymorphism in the TH gene was genotyped in 898 healthy Japanese subjects. Personality traits were evaluated using the Temperament and Character Inventory (TCI). There was no significant difference in the TCI scores of subjects with and without the T9 allele. Furthermore, no significant association was found between each genotype and the TCI scores, even when the TCI scores were compared with the homozygous genotype. These findings suggest that the (TCAT)(n) repeat polymorphism in the TH gene does not contribute to the personality traits evaluated on the TCI in healthy Japanese subjects.