OBJECTIVES: While the etiology of fibromyalgia syndrome (FMS) is unknown, the incidence of FMS has been on the rise over the years.  There is no known cure or universally accepted treatment for FMS and the treatment is typically aimed at symptom management.  Although patients with FMS are known to have higher pharmacy-related costs compared to those without FMS due to high usage of pain-relieving medications, the true financial burden on newly diagnosed FMS patients remains unclear.  The purpose of this study was to compare health care utilization and patient financial burden of FMS patients at pre- and post-diagnosis.   METHODS: Nationwide commercial claims database which includes EPO, PPO, HMO and POS managed care systems was used to identify 194 patients who were newly diagnosed with FMS in year 2008 (identified by ICD-9-CM of 729.10).  Patients with chronic comorbidities including other musculoskeletal diseases, cancer, HIV/AIDS, or asthma/COPD were excluded from the study.   Health care utilization (defined by number of outpatient medical services) and patient financial burden (defined by out-of-pocket [OOP] costs including co-pay, deductible, and coinsurance) were assessed for two time intervals – six months prior to and after the diagnosis of FMS. RESULTS: Mean age of newly diagnosed FMS patients was 44 years (SD=14) and 143 of 194 patients were females. The majority of patients (74%) were enrolled in point of service managed care systems.  FMS patients had higher health care utilization post-diagnosis when compared to pre-diagnosis but the results were not statistically significant (28 vs. 26, respectively; p=0.35).  OOP costs remained relatively unchanged for the two time periods (p=0.59). CONCLUSIONS: Patients newly diagnosed with FMS use only slightly higher health care utilization upon diagnosis of FMS when compared with pre-diagnosis period while studies involving pharmacy utilization indicate significantly higher utilization.