Low field NMR spin-lattice relaxation measurements of pore fluid were used to study pore structure during aging and drying of two silica gels. The NMR method provides in situ information concerning pore size, size distribution and surface area which is impossible to obtain by other techniques. Surface areas measured for a sol-gel sample aged in a potassium hydroxide solution were compared to similar measurements made on an ethanol aged sample during drying. Surface area and pore size distributions of the corresponding final dried gels were measured by both NMR and nitrogen adsorption/condensation. The measurements for a given sample were in good agreement. The surface area of samples before drying were much higher than after drying and the base-aged sample had a higher initial surface area than the ethanol-aged sample although after drying, this trend was reversed.