•This is the first study to investigate the sensitivity of the novel cancer-specific preference-based measures QLU-C10D in a clinical setting.•Our results show, that cancer-specific health state utility values in a myelodysplastic syndrome population may be determined using the QLU-C10D.•In general, our results inform the ongoing discussion on the arguable advantage of disease-specific over generic preference-based measures. The aim was to investigate the relative validity of the preference-based measure EORTC QLU-C10D in comparison with the EQ-5D-3L in myelodysplastic syndromes (MDS) patients. We used data from an international multicentre, observational cohort study of MDS patients. Baseline EORTC QLU-C10D and EQ-5D-3L scores were used and index scores calculated for Italy, Australia, and the UK. Criterion validity was established by Spearman and intraclass correlations (ICC) and Bland-Altman plots. Construct validity was established by the instruments’ ability to discriminate known groups, i.e. groups whose health status is expected to differ. We analyzed data from 619 MDS patients (61.1% male; median age 73.8 years). Correlations between theoretically corresponding domains were largely higher than between unrelated domains. ICCs and Bland-Altman plots indicated moderate to good criterion validity. Ceiling effects were lower for the QLU-C10D (4.7%) than for the EQ-5D-3L (22.6%). The EQ-5D-3L failed to discriminate known-groups in two and the QLU-C10D in one of the comparisons; the QLU-C10D's efficiency in doing so was higher in clinical known-groups. Results were comparable between the countries. The QLU-C10D may be suitable to generate health utilities for economic research in MDS. Responsiveness and minimal important differences need yet to be established.