Inclusion Criteria:

• Clinical diagnosis of Restless Legs Syndrome (RLS).
• Presence of increased PLMS before receiving treatment.
• Patient sleep times are between 9pm and 9am.
• Patient's RLS symptoms would occur daily if you were not on medication.

Exclusion Criteria:

• RLS secondary to other medical disorders as determined by history and physical/neurological examination.
• On a treatment (e.g., psychiatric medication) that might significantly alter RLS symptoms or study results and who cannot discontinue medication for the extended period of the study.
• History of multiple adverse drug reactions or specifically an allergy to IV iron.
• Currently experiencing a serious medical condition (chronic organ failure, active inflammation or infection, congestive heart failure, etc.) that might alter iron metabolism, would place them at risk, or interfere with study participation.
• An MRI is not possible because of medical reasons (Pacemaker; loose iron in the tissue) or concern about severe claustrophobia.
• Any condition that is likely to increase iron loss (chronic bleeding, excluding menstruation; medically necessary phlebotomy) or consumption (pregnancy).
• Serum ferritin >300mg/L or percent iron saturation >50%. This is to exclude subjects with probable hemochromatosis.
• Significant medical (e.g., inflammatory bowel syndrome; bowel dysmotility syndromes) or surgical (e.g., gastrojejunal bypass, colectomy) GI tract problems; and active chronic inflammatory processes (e.g., active hepatitis, rheumatoid arthritis, SLE). This is to exclude conditions which will potentially alter iron metabolism.