Introduction: In their previous work, the authors reported findings from 30 years on the incidence of hematological malignancies in Szabolcs-Szatmar-Bereg county, Hungary. Until now there are no other studies on this topic available in Hungary. Aim: Detailed analysis of epidemiologic features of patients with Philadelphia-negative chronic myeloproliferative disorders was carried out. Method: During a 33-year period (between January 1, 1983 and December 31, 2015) 4523 adult patients with hematologic malignancies were recorded in the leukaemia/lymphoma registry of Szabolcs-Szatmar-Bereg county. Among them, 255 patients with polycytaemia vera, 102 with primary myelofibrosis, and 331 with essential thrombocytaemia were registered. Results: The incidence of polycythaemia vera and essential thrombocythaemia in Szabolcs-Szatmar-Bereg county showed an increasing tendency, with an overall incidence rate of 1.35 and 1.75/100 000 inhabitants/year, respectively; while the incidence of primary myelofibrosis decreased in the course of years (0.54/100 000 inhabitants/year). In cases of polycythaemia vera and primary myelofibrosis the male: female ratio was found to be equal, however essential thrombocythaemia showed a female dominance. The mean age of patients with polycythaemia vera was 65 (21-95) years, similar to essential thrombocythaemia with 65 (19-85) years, and to primary myelofibrosis with 65.5 (33-84) years. There were only two villages found in this county where the occurrence of patients with Philadelphia-negative chronic myeloproliferative disorders per one thousand inhabitants was significantly higher, than the average (1.22). In every familial cases of these, the manifestation of the disease in the second and the third generations became earlier than in the first genetration. The perceived average degree of the anteposition (anticipation) was found to be 22 years. Conclusion: The epidemiologic features of Philadelphia-negative chronic myeloproliferative disorders in Szabolcs-Szatmar-Bereg county are essentially similar to data published in the literature.