Approximately 30% of 750 neonatal farmed ferret kits died without observed clinical signs. The presence of multifocal necrosis associated withToxoplasma-like organisms in the liver, lung and heart suggested a diagnosis of toxoplasmosis. Surviving animals from affected litters were stunted but showed no histological or serological evidence ofToxoplasmainfection, nor could infection be demonstrated by mouse inoculation. The involvement of animals at one day of age indicated congenitally acquired disease.