Toxoplasma gondii, a parasite, has three modes of transmission: oral intake of raw or undercooked meat or contaminated fruits and vegetables, ingestion of materials contaminated with cat feces, and transplacental infection. The focus of this article is congenital toxoplasmosis, which is transmitted to the fetus across the placenta. When primary infection of the mother occurs during pregnancy, there is a 40 percent chance of fetal infection; rate of transmission and severity of infection are related to gestational age at the time of infection. The brain and retina are often affected, and there can be a wide range of clinical disease. Amniocentesis or cordocentesis provides the most accurate diagnosis. At birth, 80-90 percent of infants with congenital toxoplasmosis are asymptomatic. But further testing may reveal retinal and central nervous system abnormalities, and there is a risk of long-term sequelae. Chorioretinitis, hydrocephalus, intracranial calcifications, and convulsions are the typical presentation of classic congenital toxoplasmosis. Serology is the most common method of diagnosing neonatal infection, but more complex tests are also utilized. The prognosis for the untreated infant is poor; however, when antibiotic therapy is started early, the rate of sequelae is reduced significantly.