Pseudotumor cerebri is a disease characterized by increased intracranial pressure, often manifested by headaches, and occasionally leading to severe visual impairment or even blindness. Most cases in adolescents, as in adults, are associated with obesity. We report a 16-year-old morbidly obese adolescent girl (body mass index 42.3 kg/m(2)) with severely symptomatic pseudotumor cerebri who had progressive visual field deficits and elevated intracranial pressure (opening pressure on lumbar puncture of 50 cm H(2)O) despite intensive medical management and placement of both ventriculoperitoneal and lumboperitoneal shunts. Six months after she underwent gastric bypass surgery, she had lost 43% of her excess body weight and had had near complete regression of her visual field deficits, along with normalization of her intracranial pressures. This case demonstrates the dramatic reversal of symptoms of pseudotumor cerebri with surgically induced weight loss. Gastric bypass should be considered as a treatment option for adolescents with severe and progressive pseudotumor cerebri.