BACKGROUND: The relationship between functional somatic syndromes and multiple somatic symptoms is unclear. PURPOSE: We assessed whether the number of somatic symptoms is a predictor of health status in three functional somatic syndromes (FSS). METHODS: In a population-based study of 990 UK adults we assessed chronic widespread pain (CWP), chronic fatigue (CF) and irritable bowel syndrome (IBS) by questionnaire and medical record data. We assessed health status (Short Form 12 and EQ-5D), number of somatic symptoms (Somatic Symptom Inventory) and anxiety/depression (Hospital Anxiety and Depression Scale) both at baseline and at follow-up 1 year later. RESULTS: The proportion of people with an FSS who also have multiple somatic symptoms (52-55 %) was similar in the three functional syndromes. The presence of multiple somatic symptoms was associated with more impaired health status both at baseline and at follow-up. This finding was not explained by severity of FSS. In the absence of multiple somatic symptoms, the health status of the FSS was fair or good. In multiple regression analysis, the number of somatic symptoms, the presence of a functional syndrome (CWP or CF) and anxiety/depression were predictors of EQ-5D thermometer at follow-up after adjustment for confounders. CONCLUSIONS: Multiple somatic symptoms in people with an FSS are associated with impaired health status and this cannot be explained by more severe functional syndrome or the presence of anxiety and depression.