In the present study the effect of sulfur dioxide pollution on phytohormonal levels and morphological changes in lichens was investigated. Fumigated sulfur dioxide was applied to Dermatocarpon intestiniforme (Korber) Hasse, Flavoparmelia caperata (L.) Hale, Lecanora muralis (Schreber) Rabenh., Neofuscelia pulla (Ach.) Essl., Rhizocarpon geographicum (L.) DC., Rhizoplaca melanophythalma (DC.) Leuck.& Poelt, Tephromela atra (Huds.) Hafellner, and Xanthophoria elegans (Link.) Th. Fr. in a glass chamber. Dermatocarpon intestinifiorma and Leconara muralis were found to be the most tolerant species.