Cat litter is formed from ground corncob granules, a clumping agent such as guar gum, and an odor control agent such as soyaethyl morpholinium ethosulfate. A water solution of the odor control agent is sprayed onto corncob granules. Thereafter, the clumping agent is slowly mixed in (without forming clumps), and excess water is evaporated off. The odor control agent is applied in a substantially uniform and adherent manner, without materially comprising absorbency or causing significant premature clumping.