We present X-ray data for all entries of the Third Catalogue of Nearby Star
s (Gliese & Jahreiss 1991) that have been detected as X-ray sources in the
ROSAT all-sky survey. The catalogue contains 1252 entries yielding an avera
ge detection rate of 32.9 percent. In addition to count rates, source detec
tion parameters, hardness ratios, and X-ray fluxes we also list X-ray lumin
osities derived from Hipparcos parallaxes.