The CD spectra of eight guaianolides from the aerial parts of Centaurea scoparia have been investigated. Most of these compounds contain a C-7, C-6 trans-fused α-methylene γ-lactone moiety and display negative cotton effects in the range of 252-271 nm for the nπ * transition of the α-methylene γ-lactone chromophore and a positive Cotton effect between 216-225 nm in case of a second chromophore in 8S-position for 4 -hydroxymethacrylates and between 241-246 nm for 4 -hydroxytiglates, which may be used for the determination of the absolute configuration of such guaianolides on the basis of spectral correlations with chlorojanerin, the absolute configuration of which was established by X-ray analysis.