Earthworms play an important role in soil quality, including forest soils. Their presence in zooedafon, as well as their abundance and species diversity, also indicate the state of the soil profile. The species diversity of the representatives of this group of macrofauna in a beech forest in the Bieszczady Mountains are recounted in this article. Earthworms were investigated in the soil of four sites selected near Ustrzyki Górne in Carpathian beech woods Dentario glandulosae - Fagetum (sites in D. g. Fagetum festucetosum, - typicum, - lunarietosum and - allietosum), every month during the annual cycle during two periods: a/ in 1986-1987 and b/ in 2009-2010. It was done according to the Zicsi’s recommendations, using the Zajonc combinated method. In the 80. thirteen earthworm species were found (total of 1 805 specimens) in the soil of four sites investigated. In decreasing order of numbers there were: Dendrobaena alpina alpina (Rosa 1984), Allolobophora cernosvitoviana (Zicsi 1967), Aporectodea rosea rosea (Sav.,1826), Aporectodea caliginosa (Sav., 1826), Lumbricus terrestris L., 1758, Octolasium lacteum (Orley,1881), Allolobophora carpathica (Cog., 1927), Fitzingeria platyura montana (Cer., 1932), Octodrilus transpadanus (Rosa, 1884), Dendrobaena octaedra (Sav., 1826), Eisenia lucens (Waga, 1857), Lumbricus rubellus (Hoffm., 1843), Dendrodrilus rubidus tenuis (Eisen, 1874). Twenty years later, in the years 2009-2010, eleven earthworm species were found in the soil of the same four sites investigated (total of 660 specimens). There was no occurrence of L. rubellus, and O. transpadanus. For all cited species, vertical distribution dynamics in an annual cycle was investigated as well as the preferred soil layer in terms of soil profile. The features of the delineated earthworm species and the soil levels they prefer allowed their affiliation with the ecological groups defined by Bouche to be considered or determined. Knowledge about the association of earthworms to ecomorphological groups in natural or a little changed ecosystem is becoming very useful, for example at the time of the reclamation of degraded soils with Lumbricidae as bioindicators.