A retrospective review was carried out of patients under 16 years old with malignant hypertension, who had been referred to a teaching hospital ophthalmology department because of reduced visual acuity. Four patients (three girls, one boy) were seen between 1994 and 2000 with a mean age at presentation of 11.5 years (range 9-15). In the short term, visual acuity improved after control of blood pressure in all four patients. However, in the long term, two patients were registered blind one to two years after presentation, one because of a choroidal neovascular membrane developing at the macula, and the other because of progressive optic neuropathy. Both of these patients had a longer duration of symptoms before diagnosis, worse visual acuity, and higher blood pressure at presentation when compared with the patients who made a good visual recovery. These observations suggest that early diagnosis of malignant hypertension in children is essential in reducing the likelihood of permanent severe visual damage.