Use of intravenous immunoglobulins (IVIG) has been recommended for treatment of RRMS if first line therapy with beta-interferon or glatiramer acetate is not tolerated, or if contraindications exist. This consensus recommendation is based on the demonstration of efficacy and tolerability of IVIG in four randomized controlled trials (RCTs). The impact of non-randomized observational trials on evidence-based recommendations for treatment is still under discussion. In order to evaluate the transferability of study results derived from RCTs into a routine practice setting, we carried out a retrospective data analysis on patients with RRMS who had been treated with IVIG during the last five years. Data sets from 308 out of 1122 screened patients were available for analysis. Treatment with IVIG resulted in a 69% reduction of the mean annual relapse rate (ARR) (calculated over two years) from 1.74+/-1.15 before IVIG treatment to 0.53+/-0.61 after start of IVIG treatment. Mean expanded disability status scale (EDSS) values remained stable throughout the observation period. The results of this observational study were similar to the results of previous RCTs with IVIG.