We have detected diffuse soft X-ray emission ( 0.4 - 1 keV ) from the disk of the spiral galaxy NGC 2403 with Chandra .
This diffuse emission ( with a total luminosity of 2.1 \times 10 ^ { 38 } erg s ^ { -1 } and a gas temperature of 2 - 8 \times 10 ^ { 6 } K ) is well separated from the numerous bright point sources .
NGC 2403 is a luminous spiral galaxy with a high rate of star formation .
Recent H I observations have revealed an extended H I halo with anomalous velocities and a general inflow towards the central regions of the galaxy .
This result and the present detection of a diffuse , hot X-ray emitting gas point at a very active disk-halo connection and galactic fountain types of phenomena .