Zirconia-phosphate aerogels were prepared by two methods : a one-step sol-gel synthesis followed by supercritical drying and an incipient wetness impregnation synthesis of a calcined zirconia aerogel. These samples were characterized by nitrogen adsorption, X-ray diffraction, infrared spectroscopy, and 1-butene isomerization. We identified both the conditions when zirconia-phosphate aerogels possess Bronsted acid sites, and the phosphate species responsible for their generation.