Frontal hypoperfusion and frontal dysfunction have been reported in patients with major depression. It was also found that frontal hypoperfusion correlated with frontal dysfunction evaluated by neuropsychological tests in depressive patients aged 60 or over. These findings suggested that depression may cause frontal dysfunction and frontal hypoperfusion, and that these pathophysiological changes are manifested as psychomotor retardation. We performed single photon emission computed tomography and Modified Stroop Test on 35 patients with depression aged 25-83 to investigate association of depressive symptoms and psychological tests with cerebral blood perfusion. Additionally, we divided the patients into a younger (less than 60 years old) and an older (60 or over) group to examine the effect of age. Significant correlations were found between frontal perfusion, interference measure on Modified Stroop Test, and psychomotor retardation in all patients. These correlations were also found in the younger group. There was no significant difference on frontal perfusion, interference measure of the Modified Stroop Test, and psychomotor retardation between the two groups. The present findings suggest that frontal hypoperfusion, frontal dysfunction, and psychomotor retardation were associated with one another in not only the old but also the young patients with depression.