In this study, Umbilicaria crustululosa (Ach.)Frey have been tesbet in resbect of their antimikrobiyel activities againts different test organisms by the steril paper dişe method. As a result ofstudy, wefound taht Umbilicaria crustulosa (Ach.) Frey revealed antimicrobiyel activities againts some bacteria especially Mycobacterium smegmatis CCM 2067 and Staphylococcus epidermidis ATCC 12228, but had no antifungal activity againts fungi used in this study.