Acute lymphoblastic leukemia (ALL) is known to cause several ocular involvements, but exudative retinal detachment is a rare complication. We describe a case report of a 4-year-old boy with T cell ALL who developed bilateral exudative retinal detachment caused by leukemic infiltration in the retinas after achieving hematological remission. Intravenous steroid pulse therapy and local irradiation reversed the condition, but it recurred concurrently with disease progression after a second relapse in the bone marrow. It is suggested that ophthalmic examination is crucial for ALL patients, especially for those whose white blood cell count is very high at onset.