Resorcinol-formaldehyde (RF) hydrogels were synthesized by sol-gel polycondensation of resorcinol with formaldehyde using a few kinds of catalysts at a gelation temperature of 238 or 332 K. RF aerogels were prepared by supercritical drying with carbon dioxide. The aerogels were characterized by nitrogen adsorption. The experimental results suggest that the gelation temperature does not greatly influence the porous properties and that sodium hydroxide and sodium hydrogencarbonate can be used as catalysts in the preparation of the aerogels.