Cross-section values for the direct and dissociative ionization of H2O by electron impact have been measured and compared with previously published data. The present measurements have been carried out from thresholds to 1 keV by utilizing a crossed electron beam and molecular beam collision geometry and an improved ion extraction technique. To the best of our knowledge, the present results for the double ionization of H2O are the first measurements. ¿ American Geophysical Union 1995