The u.v. spectra of β-amino-enones with trans-s-trans, cis-s-trans, and cis-s-cis structures are discussed. In the case of the s-trans-enone chromophore, the bathochromic shifts of β-amino-groups in the cis-position are 80–90 nm., and those of β-amino-groups in the trans-position are 60–70 nm. β-Monoalkylamino-enones show solvent effects which suggest the existence of tautomerism.