Even though ocular toxoplasmosis is the most common etiology of posterior uveitis in the United States and the world, it remains a poorly understood disease. For instance, there is limited understanding as to why macular lesions are common in congenitally infected individuals, limited understanding regarding the details of ocular recurrences, and there is no agreement on best treatment. There is no regimen that can eliminate the bradyzoite stage of infection; therefore, once an individual is infected by Toxoplasma gondii the retina is randomly undetectably seeded, resulting in a chance for local recurrences in the future. There is irreversible damage to the involved retina where a recurrence occurs. If a recurrence occurs within the central macula, the consequence is severe visual morbidity. Toxoplasma gondii is one of the most common parasitic infections in the world, with as many as one-third of all humans being infected. Currently, there is considerable controversy concerning the treatment of ocular toxoplasmosis. Some clinicians reserve treatment for active disease unless there is imminent threat to a patient's vision.