Toxoplasma gondii oocysts are environmentally resistant and can survive outdoors for many months in dry and cold climates. In the present study, sporulation and survival of T. gondii oocysts was studied in different types of cat litters commercially available in the United States. Oocysts sporulated within 2-3 days in all types of cat litters and occasionally remained viable for 14 days. Results indicate that cat litter should be changed daily to prevent sporulation and infectivity to people.