This is a non interventional, multicenter clinical trial, in adult patients receiving Tecfidera per approved SmPC and routine clinical practice. The primary objective of this study is to evaluate the total societal costs to the healthcare system related to the use of Tecfidera in RRMS patients. The study will capture data in a simple matter that can be easily interpreted providing an advantage in a country where efforts in the market access arena are in their infancy. For the aforementioned reasons, the proposed study may prove quite valuable in supporting DMF as a cost-effective therapy, valuable not only for patients but for the public health care system as well, providing all the necessary information for the evaluation that need to be examined regarding the positive reimbursement list and future decisions.

The study will take place in Greece. Investigators will participate from a broad geographical distribution in order to ensure a proper representation from all areas of Greece. Investigator's decision to prescribe DMF (Tecfidera®) (according to the indication for treatment as defined in the summary of product characteristics, SmPC and the current clinical practice), should precede entry into the study.

Inclusion Criteria:

• Persons aged 18-65 years.
• Patients with a confirmed diagnosis of RRMS.
• Patients for whom the decision to prescribe therapy with Tecfidera®, according to the locally approved product's summary of product characteristics (SmPC) has already been taken prior to their enrolment in the study. The assignment of a patient to this therapeutic strategy is not decided in advance, but falls within current practice, while the prescription of Tecfidera® is clearly separated from the physician's decision to include the patient in the current study.
• Patients must have signed an informed consent document.
• Patients must be able to read, understand and complete the study specific questionnaire.

Exclusion Criteria:

• Patients having other forms of MS, like Clinically Isolated Syndrome (CIS) or progressive forms.
• Patients who have initiated treatment with Tecfidera® more than 7 days before study enrolment or have received DMF at any different time prior to this period.
• Patients that meet any of the contraindications to the administration of the study drug according to the approved SmPC.
• Receipt of any investigational agent within 30 days or 5 half-lives of the investigational agent (whichever is longer) before the commencement of therapy with Tecfidera®.

400 previously DMF-naïve adult patients who have been diagnosed with RRMS and will initiate treatment with Dimethyl Fumarate up to 1 week before study enrolment will be included