As has long been known Berberis Sect. Wallichianae in Taiwan evidence a high species diversity all of which are endemic to the island. Though cytological data has been used to understand adaptive speciation for certain Berberis species elsewhere, little is still known about the chromosome numbers of Taiwanese Berberis. In this study, the chromosomes of eleven Taiwanese Berberis Sect. Wallichianae were counted for the first time and were all determined to be diploids (2n = 28). This result not only reconfirms previous studies elsewhere which have concluded that polyploidization may not be a dominant evolutionary process in Berberis but also suggests that geographic isolation or other extrinsic factors may play a more important role on the rapid speciation of Berberis in Taiwan.