A method for the preparation of hydrophilic silica gels with high pore volume. In the preferred method a hydrophilic silica hydrogel treated with an organosilicon compound to effect hydrophobing of the silica hydrogel is heated in the presence of an oxidizing atmosphere to a temperature sufficient to reduce the hydrophobicity imparted by the surface treatment thereby producing a hydrophilic silica gel having high pore volume.