Abstract Little is known about the pathophysiology of somatization. The authors’ aim was to explore associated factors with somatoform disorders. The authors studied 10 female patients with a diagnosis of somatization disorder or undifferentiated somatoform disorder with no comorbid current Diagnostic and Statistical Manual of Mental Disorders (4th edn) Axis I disorder and 12 healthy female volunteers. The predicting variables were temperament factors of the 240-item Temperament and Character Inventory instrument and regional brain glucose metabolism. Low novelty-seeking and high harm avoidance temperament traits and low caudate and low putamen glucose metabolism were statistically significantly associated with severe somatization (P < 0.05). In the present study, severe somatization associates with both altered brain glucose metabolism and temperament factors. No other studies on association of somatization with brain glucose metabolism and temperament have been published. The results are still considered exploratory due to the small number of subjects.