The antibacterial and antifungal activities of a series of 8-quinolinealdehyde chalcogensemicarbazones have been studied. Only the selenium analog shows activity against Gram-positive bacteria. 8-Quinolinealdehyde thiosemicarbazone becomes active against the indicated bacteria upon coordination to copper(II) ions. The antibacterial activity of the obtained complexes depends on neither the nature of the anion nor the form (molecular or anionic) of the ligand. Introduction of electron-accepting groups on the amide nitrogen atom of the thiosemicarbazide fragment leads to a substantial increase in the activity. 8-Quinolinealdehyde semicarbazone as well as its copper(II) complexes do not show appreciable antibacterial activity against the test species. All investigated compounds do not exhibit any antifungal properties.