Objective: Although the DSM-IV has provided some criteria for differential diagnosis of Hypochondriasis and Somatization Disorder, the differences between these disorders have rarely been studied. This study aimed to compare demographic and psychometric properties between hypochondriasis and somatization disorder. Methods: We investigated a sample of 100 patients aged 18-65 years who had been consecutively diagnosed as having hypochondriasis or somatization disorder via the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I). The patients completed a battery of scales to measure anxiety, depression, dissociation, and somatosensorial amplification levels. Results: The only statistically significant difference between the two groups was in terms of health anxiety. The mean Health Anxiety Inventory score was higher in the hypochondriasis group. No differences arose between the two groups in terms of other psychometric properties. Conclusions: Our results show that except for health anxiety levels, hypochondriasis and somatization disorder are similar in terms of psychological variables. The higher health anxiety levels in the hypochondriasis group support the opinions about the necessity of new categorization in these disorders.