1. The chromosome numbers of 38 species belonging to 11 genera of the tribe Campanuleae of Schönland’s system were determined. 13 of these species had not yet been investigated before. 2. A discussion is given of the differences between the present author’s results and those of other authors. 3. The systematic position of the species of Campanula with the diploid chromosome number 2n = 28 is reviewed. Some arguments are presented in favour of transferring Campanula erinus L. and Campanula drabifolia Sibth. to Dumortier’s genus Roucela. 4. A hypothetical explanation of the origin of the chromosome numbers 2n=28, 30, 32 and 34 of the genus Campanula is given. 5. The inclusion of Specularia perfoliata A. DC. and Specularia biflora Fisch. et Mey. in Triodanis is supported by cytological evidence. 6. Campanula vidalii Wats. and Campanula americana L. should be placed in the genera Azorina and Campanulastrum, respectively, both on morphological and cytological grounds. 7. The segregation of the genera Asyneuma, Synotoma, and Petromarula from Phyteuma is supported by cytological evidence. 8. The relation between the genera Campanula, Symphyandra, and Adenophora is discussed.