To test the hypothesis that the efficacy and safety of duloxetine has beneficial effects of the reduction of pain severity as measured by the average pain item of the BPI and the PGI-I in patients with fibromyalgia syndrome.

Inclusion Criteria:

• meet criteria from primary FMS as defined by the ACR: widespread aching pain in all four quadrants of the body and axial skeleton and greater than or equal to 11 of 18 tender points under digital palpation examination
• measure average pain item of the BPI at Visits 1 and 2

Exclusion Criteria:

• have pain symptoms related to traumatic injury, structural rheumatic disease, or regional rheumatic disease that will interfere with interpretation of outcome measures
• have regional pain syndrome, multiple surgeries or failed back syndrome
• have confirmed current or previous diagnosis of rheumatoid arthritis, inflammatory arthritis, or infectious arthritis, or an autoimmune disease (i.e. systemic lupus erythematosus)
• have current primary Axis I diagnosis other than major depressive disorder (MDD), including a current diagnosis of dysthymia