Previous studies have clarified that many patients with Philadelphia-negative myeloproliferative neoplasms (MPNs) have burdensome symptom profiles and accordingly impaired functioning and quality of life (QoL). In Denmark, all MPN patients are affiliated with public hospitals and because of a healthcare system financed by taxpayers these patients do not have any financial costs related to the hematological disease. Diagnoses are recorded for all patients in hospitals, and diagnosis codes are communicated to the National Patient Register (NPR). Owing to this, it was possible to contribute to the elucidation of Philadelphia-negative MPN patients’ health-related quality of life (HRQoL), by conducting a nationwide, population-based, cross-sectional HRQoL survey of these patients with cost-free access to the best available, suitable medical treatment. The survey contained validated questionnaires covering functioning, symptom burden, symptom profile, QoL, and additional questions on lifestyle. Information on comorbid diagnoses was obtained from the NPR. The participants’ HRQoL was compared to the general population. Moreover, differences in HRQoL across essential thrombocythemia, polycythemia vera, myelofibrosis, and unclassifiable MPN participants were investigated, adjusted for age, sex, comorbidity, and lifestyle. To the best of our knowledge this is the first survey of HRQoL in patients with unclassifiable MPN. A total of 2228 Philadelphia-negative MPN patients participated. The participants reported their HRQoL to be inferior to the general population, but the difference was minor. The differences in HRQoL across groups of participants with different MPN subtypes were subtle. Fatigue and sexual problems were prevalent and burdensome. Overall, participants reported a slightly healthier lifestyle compared to the general population.