The investigations were carried out in a valley on the border of the Wyspowy and Sredni (Makowski) Beskids (the Carpathians). Paramecium biaurelia was found in several streams flowing into the main river. Paramecium novaurelia was found in one habitat only. The obtained results indicate that P. biaurelia is far more typical of the examined region - than other species of the Paramecium aurelia complex occurring in the Carpathian chain. They also indicate that P. biaurelia is a pioneering species of the complex.