Multiple sclerosis (MS) is a disorder that incurs high costs to individuals, health systems and society as a whole. A growing number of studies have measured the costs of MS and assessed the cost effectiveness of different treatments. This review summarizes the evidence from these studies. Electronic databases were searched and a total of 51 studies were included, 32 of which were cost-of-illness studies. The cost-of-illness studies took different perspectives (health service or societal) and the annual costs per person with MS ranged between $US6511 and $US77,938 (year of cost 2008). Economic evaluations of interferon (IFN)-beta-1a, IFNbeta-1b, glatiramer acetate, natalizumab, mitoxantrone and cyclophosphamide were identified. The results of the cost effectiveness of drug interventions were mixed. Most results comparing a drug with placebo related to IFNbeta-1b and the results usually revealed cost-effectiveness ratios that were above usual willingness-to-pay thresholds of public decision makers. The limited evidence on glatiramer acetate suggests that this may be cost effective. Head-to-head drug comparisons produced varying results, although the findings for natalizumab appear favourable compared with other drugs. Further trial-based comparisons are required to increase the evidence base regarding drug treatments for MS.