The diagnosis of small choroidal melanomas may be difficult, and the natural history of these small tumours is poorly understood. We followed up 20 patients with the diagnosis of small choroidal melanomas for from 2 to 20 years. In 11 of these patients the melanoma was observed to grow. Nine of these patients have undergone enucleation. Eight of the eyes contained spindle B melanomas and one contained a melanoma of mixed cell type. None of the 20 patients has developed detectable metastatic disease. From this series and others reported it appears that close serial examinations without therapeutic intervention is safe in patients with small melanomas until growth is observed, and that there is little evidence to suggest that photocoagulation or radiotherapy is of greater benefit in those patients than close serial examination.