Objective: The Department of Hematology, Zealand University Hospital, Denmark, and the National Institute of Public Health, University of Southern Denmark, created the first nationwide, population-based, and the most comprehensive cross-sectional health-related quality of life (HRQoL) survey of patients with myeloproliferative neoplasms (MPNs). In Denmark, all MPN patients are treated in public hospitals and treatments received are free of charge for these patients. Therefore, MPN patients receive the best available treatment to the extent of its suitability for them and if they wish to receive the treatment. The aims of this article are to describe the survey design and the characteristics of respondents and nonrespondents. Material and methods: Individuals with MPN diagnoses registered in the Danish National Patient Register (NPR) were invited to participate. The registers of the Danish Civil Registration System and Statistics Denmark provided information regarding demographics. The survey contained 120 questions: validated patient-reported outcome (PRO) questionnaires and additional questions addressing lifestyle. Results: A total of 4,704 individuals were registered with MPN diagnoses in the NPR of whom 4,236 were eligible for participation and 2,613 (62%) responded. Overall, the respondents covered the broad spectrum of MPN patients, but patients 70-79 years old, living with someone, of a Danish/Western ethnicity, and with a higher level of education exhibited the highest response rate. Conclusion: A nationwide, population-based, and comprehensive HRQoL survey of MPN patients in Denmark was undertaken (MPNhealthSurvey). We believe that the respondents broadly represent the MPN population in Denmark. However, the differences between respondents and nonrespondents have to be taken into consideration when examining PROs from the respondents. The results of the investigation of the respondents' HRQoL in this survey will follow in future articles.