PURPOSE: Evaluation of a large series of choroidal nevi inducing the formation of a neovascular membrane in order to more clearly define the clinical presentation and to evaluate the efficacy of various treatment options. METHOD: Retrospective study of 22 clinical cases. RESULTS: All nevi were situated in the posterior choroid. They had a mean diameter of 3.8 mm and a mean thickness of 1.4 mm. Neovascular membranes were classic in all cases, extrafoveal in 13 cases (59%), and subfoveal in 9 cases (41%). A serous retinal detachment was present in every case, hemorrhages were present in 13 cases (59%), and lipid deposits were present in 16 cases (73%). All extrafoveal neovascular membranes were successfully treated by thermal laser photocoagulation. Initial visual acuity was 0.1 in three cases, 0.2-0.4 in five cases, 0.5-0.8 in four cases, and 1.0 or more in two cases. Final visual acuity was 0.1 in one case, 0.2-0.4 in one case, 0.5-0.8 in four cases, and 1.0 or more in seven cases. Five subfoveal neovascular membranes were treated either by thermal laser, photodynamic therapy, or irradiation. No treatment was applied in four cases and in one of these cases, spontaneous resolution of the neovascular membrane was observed. No growth of the pigmented tumor was observed with a mean follow-up of 4.8 years. CONCLUSIONS: Proliferation of a neovascular membrane on the surface of a pigmented choroidal tumor is a rare complication and is considered to be a relative indicator of a benign nature of the lesion. In the authors' experience, neovascular membranes are extrafoveal in more than half of cases and are accessible to laser photocoagulation. In contrast, the various modalities used to treat subfoveal neovascular membrane were ineffective and functional prognosis was unfavorable in these cases.