BACKGROUND Cerebrospinal fluid (CSF) oligoclonal bands (OB) imply intrathecal immunoglobulin synthesis and B-cell immune process. There is scarce evidence of OB having a role in disease prognosis. The objective of the present study was to determine OB's prognostic value regarding disease progression. METHODS Between January 1994 and January 2007, relapsing-remitting MS (RRMS) patients in which OB were determined were included. Demographic, clinical aspects and presence of OB were analyzed. We compared OB+ versus OB- patients regarding progression to expanded disability status scale (EDSS) of 6·0 and to secondary progressive MS (SPMS). Cox proportional hazard models were used to compare the outcome between groups. P values <0·05 were considered significant. RESULTS One hundred and ninety-six patients were included. In 176 patients (90%), the CSF showed type II OB, 20 (10%) patients were OB negative. There were no differences between age, clinical presentation and EDSS at onset or in the immunomodulatory treatment received between OB+ and OB- patients. Sixty-two (31·6%) patients converted to SPMS during the follow-up, 59 (33·5%) were OB+ and 3 (15%) were OB-. EDSS of 6 was recorded in 56 (28·5%) patients during the follow-up; 54 (31%) were OB+ while only 2 (10%) OB- patients reached this outcome (reach SP phase, P = 0·032; HR: 2·2; 95% CI: 1·3-7·5 and EDSS of 6, P = 0·037; HR: 1·9; 95% CI: 1·3-8·5). CONCLUSIONS We observed during the follow-up that OB- patients had a better prognosis and milder disability compared to OB+ patients.