A high performance liquid chromatographic (HPLC) method, based on dansylation and fluorescence detection, is described for the estimation of putrescine, spermidine, and spermine in lichen (Evernia prunastri [L.]) samples. Because of the high concentrations of phenols and salts, dansylation was followed by a pre-HPLC purification step. Both flow rate and mobile phase (methanol:water) followed a gradient for optimum resolution on a reverse-phase column. Amounts as small as 0.3 picomole of standard polyamines could be detected. In applying the method to lichens, it was found that 5.45% (w/w) of the exogenous putrescine taken up by the thallus was unbound in the algal partner and that 60% (w/w) was conjugated in the thallus, perhaps to lichen phenolics.