Inclusion Criteria:

• Subject is male or female between the ages of 18 and 65, inclusive
• Subject has an IHS diagnosis of migraine with or without aura for at least one-year prior to screening
• Subject has experienced between 4 and 10 migraine headaches per month (inclusive) over the past six months, with at least 24 hours separating attacks
• Subject has less than 15 total headache days per month
• Subject is able to differentiate migraine attacks from other headache types, if applicable
• Subjects daily medications (for any indication) have remained at a stable dose for the 60 days preceding screening
• Subject is using or agrees to use for the duration of participation a medically acceptable form of contraception (as determined by investigator and mutually agreed upon with patient), if female of child-bearing potential
• Subjects currently taking a single agent for the prevention of migraine must be on a stable dose (unchanged for 2 months) prior to study entry
• Subject has negative urine pregnancy test prior to study entry, if female of child-bearing potential
• Subject is able to understand and comply with all study requirements
• Subject provides written informed consent prior to any screening procedures being conducted

EXCLUSION CRITERIA:

• Subjects with onset of migraine after 50 years of age
• Subjects who have been previously treated or are currently being treated with duloxetine
• Subjects who have failed greater than 3 adequate trials of other medications the prevention of migraine, as determined by investigator
• Subjects who have a known hypersensitivity to duloxetine or any of the inactive ingredients
• Subject has taken any medication which has been shown to be effective for migraine prophylaxis, on a daily basis within the 4 weeks prior to screening or at any time during participation in the study, for any indication.
• Subjects with a history of significant drug or alcohol abuse within the past year
• Subjects with major depressive disorder or who have had a suicidal ideation in the 3 months prior to screening or have a history of attempted suicide
• Subjects who have a Beck Depression Inventory score of > 18 at screening
• Subjects who have > 0 on question number 9 of Beck Depression Inventory (Suicidal Thoughts or Wishes question)
• Subjects who have participated in an investigational drug trial in the 30 days prior to the screening visit
• Subjects with a current or history of a hepatic or renal disorder
• Subjects with uncontrolled narrow angle glaucoma
• Subjects who have experienced significant side effects from two different SSRI and/or SNRI therapies, as determined by investigator
• Subjects with uncontrolled restless legs syndrome, as determined by investigator