We report on follow-up spectroscopy and photometry of the cataclysmic variable candidate HS 0907+1902 selected from the Hamburg Quasar Survey. B, V, and R photometry obtained during the first observed outburst of HS 0907+1902 (V approximate to 13) reveals deep eclipses (Delta V approximate to 2.1 - 2.8) and an orbital period P(orb) = 4.2 h with the eclipse depth decreasing to the red. The outburst eclipse profiles are symmetric, indicating an axisymmetrical brightness distribution in the accretion disc. We derive an inclination i approximate to 73 degrees - 79 degrees from the eclipse duration. The quiescent spectrum obtained with the Hobby-Eberly Telescope shows double peaked emission lines of H I, He I and Fe I,II and clearly identifies the system as a dwarf nova. Absorption features of the secondary star are detected at red wavelengths from which a spectral class M3 +/- 1.5 and a distance of d = 320 +/- 100 pc are derived.