Interactions of H2O with SrTiO3(100) surfaces were investigated using temperature-programed desorption (TPD) spectroscopy. TPD spectra show that water desorbs below 300 K on stoichiometric TiO2-tcrminated SrTiO3(100) surfaces. TPD features at 200-300 K are attributed to the nondissociative adsorption of H2O on cation sites while the TPD feature at 160 K is assigned to the desorption of multilayer water. However, TPD spectra for H2O on reduced SrTiO3(100) surfaces exhibit additional desorption features at 300-500 K, resulting from the dissociative adsorption of water. Comparisons of TPD spectra for H2O on SrTiO3(100) with unreconstructed TiO2(110) and (100) surfaces reveal a structural influence on the water adsorption and desorption behavior.