[en] The natural frequencies and collapse strength of radioactive waste transport casks are analyzed by means of finite element method. The calculated casks are those for high, intermediate and low level waste. The natural frequencies are obtained in two cask-positions, vertical and horizontal. The buckling or collapse strength is analyzed under external pressure. MARC is used as a finite element program. Conclusions obtained are as follows. (1) The natural frequencies calculated by the handbook formulas of beams can be considerably higher than those by finite element method in case of bending mode shapes. (2) The vibration modes of the casks for low or intermediate level waste are mainly the deflection of lid and bottom plates, whose natural frequencies can be estimated by the handbook formulas of circular plate. (3) The collapse strength of casks can be obtained by elastic buckling analysis in case of the cask for low level waste with small rigidity, or by non-linear analysis in case of the cask for high or intermediate level waste with large rigidity. (4) The collapse modes in non-linear analysis are same as the first modes in elastic buckling analysis. (author)