The development of National clinical guidelines on diagnosis and treatment of Ph-negative myeloproliferative neoplasms provides the knowledge basis for decision making in diagnosis, therapy, prevention, and rehabilitation in compliance with evidence-based medicine principles in order to ensure appropriate medical care in a particular clinical setting. The clinical guidelines underly the choice of optimal methods of diagnosis, therapy, prevention, and rehabilitation as part of a patient’s medical care, the development of criteria for the assessment of medical care quality, medical care standards, medical care procedures, setting standards on equipment and management of diagnostic and therapeutic procedures, and provision of continuous medical education and advanced training for healthcare professionals. In 2013, a working group was formed to develop and formulate clinical guidelines on the treatment of myeloproliferative neoplasms. These guidelines were first published in 2014, afterwards they were revised and republished. The dynamic development of current hematology presupposes constant updating of knowledge and implementation of new diagnosis and treatment methods in clinical practice. In this context, clinical guidelines present a dynamic document to be continuously amended, expanded, and updated in accordance with scientific findings and new requirements of specialists who are directly involved in treatment activities. The present edition is an upgraded version of clinical guidelines with updated information on classification, diagnosis, prognosis, current methods of therapy, and their efficacy and tolerability assessment. The guidelines are intended for oncologists, hematologists, healthcare executives, and medical students.