The evolution of Chernobyl103Ru,134Cs and137Cs in accumulated fallout is rigorously followed. The103Ru activity of about 12 kBq.m–2 in the middle of May 1986 became insignificant at the end of 1986, while the levels of134Cs and137Cs have changed during 3 years from 2.5 kBq.m–2, respectively, 5 kBq.m–2 to about 0.9 kBq.m–2, respectively 4.7 kBq.m–2 according to their proper half-lives.