Sol-gel boehmite was aged under hydrothermal conditions at 200 degreesC using water as mineralizer agent. Samples were characterized with X-ray powder diffraction, nitrogen adsorption, and transmission electron microscopy. Calcined solids were also studied by infrared spectroscopy of adsorbed pyridine. Their catalytic properties were determined in the 2-propanol decomposition. The hydrothermal treatment ordered the atoms of the sol-gel boehmite mainly in two dimensions forming thin crystallites, which grew as treatment time increased. Due to the pseudomorphic transformation of boehmite into gamma-alumina, the arrangement of crystallites in the corresponding boehmite determined alumina particle morphology and porosity. The pore size distribution was narrow, and the pore size shifted to larger values as the time of hydrothermal treatment increased. The strength and number of acid sites depended also on the treatment time. The catalytic activity correlated well with the acidity and specific surface area.