Abstract: Nuclear DNA content of Trachelium jacquinii subsp. dalgiciorum, an endemic taxon, was analysed using flow cytometry. Plants were collected from a natural population. While some plants were prepared as herbaria material, others were placed in pots and incubated in growth chamber. Fresh leaves for flow cytometry analysis were chopped in MgSO4 buffer (with dithiothreitol, propidium iodide and triton x-100) on ice in a Petri dish and stained with propidium iodide (with RNase-DNase free). Stained nuclei were analysed on an EPICS XL (Beckmann Coulter) model flow cytometer. The mean DNA content per plant was based on 10000 scanned nuclei. Nuclear DNA content (2C-value) of Trachelium jacquinii subsp. dalgiciorum was found as 3.44±0.14 pg (1C-value 1.72 pg). This study contributes present data on nuclear DNA content of angiosperm taxa.