A rapid, sensitive and specific high-performance liquid chromatographic method for the simultaneous separation of natural adenosyl-sulphur compounds has been developed. The compounds were separated by using the strong cation-exchange resin Partisil 10 SCX with isocratic elution. The adenosyl-compounds were monitored by an ultraviolet detector operating at 254 nm. Sensitivity was greater than 50 pmoles for all compounds tested and standard curves were found to be linear for concentrations of up to 50 nmoles. The method can be applied to biological samples for the estimation of S-adenosyl-L-methionine,S-adenosyl-L-homocysteine and S-adenosyl-(5')-3-methyl-thiopropylamine and for measurement of enzyme activities involving the above-mentioned compounds.