The Multiple Sclerosis Database Network (MSDN) is the first Italian multiple sclerosis (MS) registry. The preliminary results on the MSDN cohort demonstrated that the risk of disability progression, in a sample of 2090 MS patients, was reduced by about four- to five-fold in patients exposed to IFNbeta for more than 4 years compared with patients exposed for up to 2 years. More recent results showed, in a subset of 1170 relapsing-remitting MS patients, of whom 918 were treated with IFNbeta and 252 were untreated, that IFNbeta-treated patients had a differential reduction in EDSS score change of -0.055 for each year of follow-up in comparison with the untreated group. These results provide significant information on the effectiveness of IFNbeta treatment on long-term disability progression in MS.