An outbreak of systemic toxoplasmosis occurred in October 1977 in Atlanta, Georgia. Thirty-seven people became ill and/or had serologic evidence of acute infection. Epidemiologic study by the Center for Disease Control (CDC) suggested that toxoplasma oocysts from infected cats in a riding stable were the source of infection. Aerolization of oocysts or hand-to-mouth contact were the presumptive means of transmission. All patients were examined and followed for over a year, without evidence of toxoplasma retinochoroiditis. In a four-year follow-up study, only one patient had shown evidence of ocular disease. This suggests that at least some sporadic cases are due to acquired toxoplasmosis.