The aim of this study was to compare Betula pollen seasons in 2019 in 12 cities located in different regions of Poland. Pollen monitoring was conducted in Bialystok, Bydgoszcz, Cracow, Lublin, Olsztyn, Opole, Piotrkow Trybunalski, Sosnowiec, Szczecin, Warsaw, Wroclaw, and Zielona Gora. Airborne pollen was monitored by the volumetric method using Burkard or Lanzoni pollen samplers. Pollen season length was determined by the 98% method. The pollen season start date was recorded earliest in Wroclaw and Zielona Gora, and latest in Bialystok. The highest Betulapollen concentration values were found in Lublin, whereas the lowest ones in Bialystok. In most of the cities, the maximum daily Betula pollen concentration was recorded on April 19th or 20th. Exceptionally, in Wroclaw the peak value occurred on April 8th, while in Bialystok as late as April 29th. The annual pollen sum reached the highest values in Warsaw and the lowest ones in Bialystok. The highest risk of allergy in people sensitive to the pollen of this taxon was found in Bydgoszcz, Zielona Gora, Szczecin, Opole, and Warsaw