OBJECTIVE: IRLS is used for clinical assessment and severity of Restless Legs Syndrome (RLS). To compare the burden of RLS with other health states, this study has mapped the IRLS to a multi-attribute utility measure, the EQ-5D. METHODS: Four RLS experts from Spain, France, UK and US were identified to participate in mapping the ten IRLS items (each with five ordinal response levels) to the five EQ-5D domains (each with three ordinal response levels). A pilot study conducted by one expert identified two issues: 1) the disease characteristics of RLS and the 10 IRLS items could not be mapped to EQ-5D domains of ‘Self-care’ and ‘Mobility’ (EQ-5D level ‘1’ was assigned to both), and 2) IRLS question three (relating to relief from movement) proved difficult to map; an algorithm to map this was developed. All experts then completed their individual mapping responses. Discrepancies were resolved through consensus resulting in one final mapping response. RESULTS: The experts concluded that the EQ-5D domains of ‘Pain/Discomfort’, ‘Usual Activities’ and ‘Anxiety/Depression’ were appropriate for mapping to the 10 IRLS items (each item mapped once) . ‘Pain/Discomfort’ mapped to four IRLS items, ‘Usual Activities’ mapped to five IRLS items and ‘Anxiety/Depression’ mapped to one IRLS item. Ordinal responses for each IRLS item were mapped to appropriate ordinal responses on the three EQ-5D domains. EQ-5D utilities could be established for different combinations of IRLS item responses and corresponding IRLS total scores. Using trial data, a significant correlation between IRLS total scores and EQ-5D utilities was established (r = - 0.84, p <0.0001). CONCLUSION: Based on clinical consensus, the IRLS can be successfully mapped to the EQ-5D. The algorithm resulting from this work may be used to compare health related QoL of RLS sufferers with those of other diseases for resource allocation decisions.