After the Chernobyl nuclear accident in 1986, 14 lichen specimens collected from Trabzon and Rize in 1995 were used to detect the amount of the fallout radionuclides. In this paper, radioactivity levels in the same species from the same localities were re-detected to compare with those of 1995. According to the results of the two studies, the radioactivity levels that this paper found for 137Cs and 40K are significantly lower than those of 1995 (about 5.5–127 folds for 137Cs, 5–17 folds for 40K). The level of 212Pb was acceptably small. The highest activities of the lichen species are seen in the locality of Helvacı (Trabzon, 100 m) and C¸ amlıhems¸in (Rize, 1850 m) while the activities are medium in Bozdog˘an (Trabzon, 150 m), Kemaliye (Trabzon, 750 m) and C¸ amlihems¸in (Rize, 900 m). The activity values generally increase significantly depending on the altitudes. Since the measurements were performed 20 years after the Chernobyl accident in 1986, radionuclides of 134Cs having short half-life (2.062 y) have not been detected. All data was obtained with a coaxial high purity Ge detector of 15% relative efficiency and resolution 1.9 keV at the 1332 keV gamma of 60Co (Canberra, GC 1519 model). Keywords Chernobyl
Fallout
137Cs
Turkey.