Two patients with choroidal hemangiomas developed choroidal neovascularization. One patient with Sturge-Weber syndrome, a unilateral diffuse choroidal hemangioma, and a serous detachment of the macula was treated with yellow dye laser photocoagulation in a grid pattern to the tumor before glaucoma filtration surgery. Four years after successful laser treatment, the patient developed subfoveal choroidal neovascularization in an area of treatment. A second patient with a circumscribed choroidal hemangioma developed spontaneous subfoveal choroidal neovascularization 12 years after initial diagnosis of the hemangioma. The development of choroidal neovascularization associated with choroidal hemangiomas represents a potential cause of poor visual outcome in these patients.