Methods for purifying adenoviruses from a contaminated sample using a hydroxyapatite medium are provided. Sodium chloride concentrations present in buffers used throughout the method are at least 150 mM to prevent the adenovirus from irreversibly binding to the hydroxyapatite. Levels of contaminants and empty adenovirus capsids from samples purified by conventional purification techniques are further reduced to provide a highly pure adenovirus preparation.