Activity concentrations of radionuclides in the atmosphere have been monitored for over 21 years in the Czech Republic, at present at 10 sampling sites. Results of long-time observation of the radionuclides (137)Cs, (7)Be, (210)Pb, (22)Na, (40)K, (238)Pu, (239,240)Pu, (90)Sr, (85)Kr and (14)C and statistical analysis of the data from the monitoring site in Prague are given in the paper. In 2007 mean activity concentrations of monitored radionuclides at Prague monitoring site in Bq/m(3) were: (85)Kr, 1.6 x 10(+0); (14)C, 5.3 x 10(-2); (137)Cs, 6.8 x 10(-7); (7)Be, 4.3 x 10(-3); (210)Pb, 5.3 x 10(-4); (40)K, 1.8 x 10(-5); (22)Na, 3.5 x 10(-7); (90)Sr, 5-7 x 10(-8); (238)Pu, 1-2 x 10(-10) and (239,240)Pu, 1.7 x 10(-9).