EN
Report on nature impressions from the expedition to the northern Masovia in the frames of „Atlas of the distribution of the dragonflies (Odonata) of Poland" project. The studies covered 124 study sites and resulted in recording 55 dragonfly species. However, the studied area was strongly transformed - especially this referred to small water courses. Melioration and pollution were probably the main reasons why Calopteryx virgo was found as a very rare species. Erythromma viridulum, Lestes barbarus, Aeshna juncea, A. subarctica elisabetluie, A. viridis, Orthetrum albistylum and O. brunnewn were the most interesting species recorded during studies.