A new 53-item instrument for the evaluation of treatment effects in somatoform disorders, the Screening for Somatoform Symptoms-7 (SOMS-7), is presented. It covers all somatic symptoms mentioned as occurring in somatization disorder, according to DSM-IV and ICD-10. A group of 325 patients was assessed at the beginning and end of treatment to compute scores of reliability and validity. The new scale showed high internal consistency (alpha=0.92) and revealed two composite indices: somatization symptom count and somatization severity index. These indices discriminated patients fulfilling complete criteria for somatoform disorders, patients with somatization syndrome, and patients with other mental and psychosomatic disorders. The instrument confirmed symptom reductions between admission and discharge, while in another group composed of wait-listed patients, no significant decrease in symptoms was observed. In sum, the SOMS-7 seems to be a comprehensive, reliable, and valid instrument for the evaluation of treatment effects in patients with somatoform disorders.