The aim of our study was to estimate the costs of multiple sclerosis (MS) in Poland according to severity of disease. Total, direct and indirect costs were compared in 148 patients divided into three groups categorized by disease severity: stage I Expanded Disability Status Scale (EDSS <3.5), stage II (EDSS 4.0-6.0) and stage III (EDSS >6.5). Cost evaluation was performed from the societal perspective and covered the 5-month period. Simple sensitivity analysis was performed by varying the tariffs and valuing caregiving at 40% of the average wage. The mean total cost/patient for 5 months was estimated at 10,955, 15, 603 and 18, 464 PLN for stage I, II and III, respectively [exchange rate: 4 PLN=1 EUR; purchasing power pariety: 1 EUR=2.05 PLN] (P <0.0001). Regardless of EDSS stage indirect costs exceeded direct costs. Both direct and indirect costs increased with MS progression. For indirect cost the main item was productivity loss. This study confirms that MS represents a high economic burden, with indirect costs greatly exceeding direct costs. As costs increase with disease progression, treatment efforts should focus on patients in the early stages of MS.