A new series of the cone-shaped tetraalkoxycalix[4]arenes substituted at the wide rim with four phosphomethyl groups have been synthesized by the Arbuzov, Michaelis-Becker and Aterthon-Todd reactions of the chloromethyl or phenylhydrophosphinylmethylcalix[4]arenes. Their binding properties towards Eu ³⁺ and Am ³⁺ cations were investigated by the liquid-liquid extraction method. Due to the 'calixarene effect' the tetraphosphorylated calixarenes are more effective extractants for the metal cations than their acyclic analogs or some industrial extractants such as trialkylphosphinoxides, carbamoylphosphinoxide, bis-2-diethylhexyl phosphoric acid.