A variable number of tandem repeats (VNTR) in the second intron of the serotonin transporter gene (STin2) has been studied in association with the susceptibility to affective disorders. Recently, it was reported that selective serotonin reuptake inhibitors were more effective in patients with major depressive disorder having the homozygous allele pair (12-copy/12-copy) of VNTR in the STin2 than in ones having other allele combinations. As the study had methodological problems, further studies are needed to confirm the above finding. Therefore, the authors investigated whether the allelic variation of VNTR in the STin2 was associated with the antidepressant response to fluvoxamine in 66 patients with major depressive disorder. Fluvoxamine was prescribed up to 200 mg/day in the dosing protocol for 6 weeks. The present study showed no significant association between the polymorphism of VNTR in the STin2 and the treatment response to fluvoxamine.