The Swiss bryophyte collection of Paul Culmann in the herbarium Zurich (acronym: Z) has been digitalised and the data are now stored in a relational database. The collection contains 12,536 specimens with detailed information on locality, altitude, collecting date, and ecology. The specimens were collected between 1876 and 1923. They belong to 756 taxa, which is 69 % of the taxa known today from Switzerland. From a systematic point of view they well represent the Swiss bryophyte flora, as nearly all families are covered and there is no bias on either liverworts or mosses. Geographically, the data are less even distributed, because Paul Culmann collected preferentially in two regions: the canton of Zurich and the “Berner Oberland” (southern, alpine part of the canton of Bern). Therefore, many of his specimens are from higher altitudes, whereas lower regions are underrepresented. Despite the uneven geographical distribution, the data are a most valuable source for analysis of changes in the bryophyte flora of Switzerland.