© 2020, İstanbul Medipol University. All rights reserved.Cistus creticus L. is a well-known member of the Cistaceae family. In this present study, methanol extract of aerial parts of C. creticus was evaluated for its antifungal activity against plant pathogenic fungi such as Fusarium moniliforme NRRL 2374, Fusarium culmorum NRRL 3288, Alternaria alternata ATCC 6663, and Botry-tis cinerea AHU 9424, respectively. The in vitro antifungal activity of C. creticus extract was determined by calculating mycelial growth inhibition. It was demonstrated that methanol extract of C. creticus has shown antifungal activity on F. mon-iliforme (36,7%) and B. cinerea (30,2%). Moreover, we are planning to evaluate the active fractions which are responsible for the antifungal activity in further studies.