To evaluate the tolerability of a new formulation of rebif and Betaseron in subjects with relapsing-remitting multiple sclerosis (RRMS) by comparing the mean change in injection site pain scores from pre-injection to 30 minutes post therapy administration.

Inclusion Criteria:

1. Subject with diagnosis of RRMS according to McDonald criteria or Poser

2. Subject is between 18 and 60 years old inclusive

3. Subject is willing to follow study procedures

4. Subject has given written informed consent

5. Female subjects must be neither pregnant nor breast-feeding and must lack childbearing potential, as defined by either:

   • Being post-menopausal or surgically sterile, or
   • Using a hormonal contraceptive, intra-uterine device, diaphragm with spermicide, or condom with spermicide, for the duration of the study.

Exclusion Criteria:

1. Subject has Clinically Isolated Syndrome (CIS), Primary Progressive MS, or Secondary Progressive MS without superimposed relapses.
2. Subject has had any prior interferon beta therapy (either beta-1b or beta-1a) prior to study Day 1.
3. Subject received any other approved disease modifying therapy for MS (glatiramer acetate) or any cytokine or anti-cytokine therapy within the 3 months prior to Study Day 1.
4. Subject received immunomodulatory or immunosuppressive therapy (including but not limited to cyclophosphamide, cyclosporin, methotrexate, azathioprine, linomide, mitoxantrone, teriflunomide, natalizumab, laquinimod, Campath and cladribine) within the 12 months prior to Study Day 1.
5. Subject had prior use of Cladribine or has previously received total lymphoid irradiation.
6. Subject has known allergy to natural or recombinant interferon or any other component of formulation excipient(s) of Rebif® or Betaseron®: Mannitol, Poloxamer 188, Methionine, Benzyl alcohol or Albumin (human).
7. Use of any other injectable medications on a regular basis during the week prior to the screening period or during the screening or treatment periods. Receiving a single injection for treatment or prophylaxis of a condition unrelated to the subject's multiple sclerosis or the subject's Rebif® or Betaseron® therapy (e.g. receiving a influenza or pneumococcus vaccination) is acceptable.
8. History of any chronic pain syndrome.
9. Subject has any other disease apart from MS that could better explain the subjects signs and symptoms.
10. Subject has complete transverse myelitis or bilateral optic neuritis.
11. Subjects who used any investigational drug or experimental procedure within 12 weeks prior to visit 1.
12. Subject has inadequate liver function, defined by a total bilirubin, aspartate aminotransferase (AST) or alanine aminotransferase (ALT) or alkaline phosphatase > 2.5 times the upper limit of the normal values.
13. Subject has inadequate bone marrow reserve, defined as a white blood cell count less than 0.5 x lower limit of normal.
14. Subject suffers from current autoimmune disease (other than RRMS).
15. Subject suffers from major medical or psychiatric illness that in the opinion of the investigator creates undue risk to the subject or could affect compliance with the study protocol
16. Subject is pregnant or attempting to conceive
17. Visual or physical impairment that precludes completion of diaries and questionnaires.
18. Subject received oral or systemic corticosteroids or ACTH within 30 days of visit 1.