The primary objective of the study is to determine physician reported persistence with the Avonex PEN at Month 12/End of Study as well as determining factors associated with persistence. The secondary objectives for this study are as follows: To evaluate the tolerability for treatment administration of the Avonex PEN at Months 3, 6, and 12; To evaluate patient quality of life (QoL) while using the Avonex PEN for treatment administration at Months 3, 6, and 12; To evaluate clarity of directions for use of the Avonex PEN at Month 3; To evaluate ease of use and the patient's assessment of the injection procedure with the Avonex PEN at Months 3, 6, and 12; To evaluate patient reported adherence at Months 6 and 12; To evaluate physician reported persistence at Month 6; To evaluate overall patient satisfaction with the use of the Avonex PEN for treatment administration at Months 3, 6, and 12; To evaluate patient reported fear of injection at Months 3, 6, and 12; and To evaluate the percentage of patients switching from caregiver to self-injection at Months 3, 6, and 12.

Inclusion Criteria:

• Ability to understand the purpose and risks of the study and provide signed and dated informed consent
• Must satisfy the locally approved therapeutic indications for the Avonex PEN
• Decision to treat with Avonex PEN must precede enrollment
• Must have no more than two (2) injections with the Avonex PEN prior to enrollment

Exclusion Criteria:

• Inability to comply with study requirements
• Other unspecified reasons that, in the opinion of the investigator or Biogen Idec, make the patient unsuitable for enrollment

Multiple Sclerosis patients who have made the decision, along with their health care provider, to begin therapy with Avonex PEN.