Polyamines putrescine, spermidine and spermine are present in all living cells and are unique low molecular weight metabolites, which carry multiple positive charges at physiological conditions. Recent studies confirmed the notion that increased polyamine synthesis as a response to environmental clues is beneficiary for a plant stress resistance. Yet molecular targets for polyamine action in plant cells remain elusive. On the other hand, in animal cells endogenous polyamines affect a large variety of cationic channels, thus controlling their physiological functions. Similar studies in plant systems revealed that polyamines affect certain K⁺ and non-selective cationic channels in plasma membrane and tonoplast, as well as the plasma membrane H⁺-ATPase. This review summarizes the modes of polyamine actions on these ionic transporters and discussed their possible implications in a plant response to abiotic stresses, with a special emphasis to drought, salt stress, and K⁺ starvation.