Ten red ruffed lemurs (Varecia rubra)—two adult females and their eight offspring—were evaluated in this case series. Two adult females were diagnosed with chronic, latent toxoplasmosis based on serologic testing. The first female lemur had two successive pregnancies. The first pregnancy resulted in transplacental transmission of Toxoplasma gondii. The only surviving offspring was diagnosed with congenital toxoplasmosis based on serologic testing and compatible ophthalmic lesions. The two deceased offspring had disseminated nonsuppurative inflammation and intralesional protozoal organisms consistent with T. gondii, which was confirmed by polymerase chain reaction. The second pregnancy did not result in transplacental transmission. The second chronically infected adult female lemur had one pregnancy that resulted in a single stillborn fetus without evidence of transplacental transmission of T. gondii. Treatment with trimethoprim-sulfamethoxazole and folinic acid was administered to the first adult female and one offspring, but no treatment was given to the second adult female. All surviving lemurs had no further complications associated with toxoplasmosis. This case series demonstrates that chronic, latent infection of reproductive female red ruffed lemurs with T. gondii may result in variable outcomes: (1) transplacental transmission with disseminated fetal infection and stillbirth, (2) transplacental transmission with congenital infection and survival, or (3) lack of transplacental transmission and healthy offspring. Information gained from these cases may help guide recommendations for breeding of this critically endangered species.