The main goal of this open-label, prospective, non-controlled, non-interventional post marketing surveillance study is to evaluate how pramipexole treatment works when applied in actual practice. In actual practice patients who would have been excluded in the clinical registration studies of pramipexole in moderate to severe primary Restless Legs Syndrome (i.e. those with certain disease histories, co-morbidities and/or demographic characteristics) will also be treated with pramipexole. Thus, during this post marketing surveillance study additional information on the efficacy and safety of pramipexole in those patients will be obtained. The objectives of this post marketing surveillance study are:

• To investigate the influence of Sifrol® (pramipexole) treatment on unpleasant sensory symptoms of Restless Legs Syndrome as measured with the short form of the McGill Pain Questionnaire.
• To assess if improvement of sensory symptoms correlates with overall Restless Legs Syndrome severity (International Restless Legs Syndrome Scale for Severity) and with secondary symptoms like sleeping problems and daytime tiredness (items 1 & 6 from Restless Legs Syndrome-6).
• To evaluate if the treatment effect of Sifrol on overall Restless Legs Syndrome severity (International Restless Legs Syndrome Scale for Severity) differs between patients with high pain scores and patients with lower pain scores.
• To compare General Practitioner and neurologist sites patient populations in terms of demographics, Restless Legs Syndrome severity at Visit 1 and treatment outcomes at Visit 3.
• To evaluate the development of behavioural changes under pramipexole treatment.

Study Design:

Inclusion criteria:

1. Diagnosis of primary moderate to severe Restless Legs Syndrome.
2. Patients who are planned to be treated with Sifrol® (pramipexole) and where the decision of treatment is made independent of the patients' inclusion into this post marketing surveillance study.
3. Male or female patients aged at least 18 years.
4. Written informed consent by the patient for study participation.

Exclusion criteria:

1. Any contraindications according to the Summary of Product Characteristics: hypersensitivity to pramipexole or to any of the excipients.
2. Previous or ongoing treatment with Sifrol® (pramipexole).
3. Previous or ongoing treatment with dopamine receptor agonists.

RLS patients