PURPOSE: To assess EQ-5D-5L (5L) validity in patients with acute stroke, in comparison with EQ-5D-3L (3L). METHODS: Cross-sectional study of 408 patients during index hospitalization. We compared 5L and 3L in terms of feasibility, frequency of unique health states, ceiling effect and discriminatory power (informativity). We assessed construct validity in terms of known-groups validity and convergent validity of 5L dimensions with other stroke outcome measures. RESULTS: The overall proportion of patients with acute stroke reporting 'no problems' with 3L-6.1 % was further reduced to 5.6 % with 5L (relative reduction of 8.2 %). The highest improvement in relative discriminatory power, when moving from 3L to 5L, was noticed in pain/discomfort and anxiety/depression dimensions (Shannon Evenness Index 0.91 for both 5L dimensions; relative increase 34.4 and 29.1 %, respectively). Known-groups validity tests confirmed prior hypotheses: Health state utilities were lower in following subpopulations-females, patients with high modified Rankin Scale (mRS) score, low Barthel Index (BI) or VAS score, patients with subarachnoid hemorrhage or intracerebral hemorrhage, and when proxy respondent was used. Convergence of EQ-5D-5L dimensions with mRS, BI and EQ VAS was improved or at least the same as for 3L dimensions. CONCLUSIONS: Results support the validity of the EQ-5D-5L descriptive system as a generic health outcome measure in patients with acute stroke, demonstrating some psychometric advantages in comparison with EQ-5D-3L.