OBJECTIVES:   Haemophilia A, a congenital reduction in blood factor VIII concentration, results in more frequent and sustained bleeding, with the impact greatest in patients with the lowest levels of factor VIII. Repeated bleeding in joints leads to accumulated damage, arthropathy, and disability. We aimed to determine health status in these patients. METHODS:   The Cost of Haemophilia across Europe Socioeconomic Survey (CHESS) study collected detailed clinical and health economic data for 996 adult males with severe haemophilia A; 426 also completed a patient-reported outcomes survey. Subgroup analyses of the EQ5D questionnaire were conducted to evaluate whether impairment of health status differed according to age category or treatment regimen. Descriptive analyses only were performed due to low subgroup size. RESULTS:   Of the 426 patients who completed the EQ5D questionnaire, most (69%) had initially received episodic treatment, with 47% subsequently switching to a prophylaxis. Only 14% had always received prophylactic treatment (14%) or had switched from prophylaxis to episodic treatment (17%). Across all EQ5D dimensions, a significant proportion of patients had impaired health status, particularly with pain (63% of participants). Levels of severe impairment overall were lowest in patients who had always received prophylactic treatment but highest in those who had switched from episodic to prophylactic treatment as adults. Across all age categories (18-29, 30-44, 45-59, 60+ years), there were moderate or severe levels of impairment in mobility (22-71%), self care (8-57%), anxiety and depression (34-64%), pain and discomfort (52-71%) and usual activities (20-51%), though the oldest age category had the highest levels of the most severe levels of health impairment (4-9% across all dimensions). CONCLUSIONS:   The EQ5D survey showed a significant burden of severe haemophilia A across all adult age categories. Consistent with previous publications, patients who had always used a prophylactic treatment regimen had the least severely impaired health status.