The first published case from Norway of primary bilateral malignant melanoma of the choroid is presented. On the admission of a 73-year-old woman for a choroidal melanoma of the left eye, an asymptomatic tumour was detected in the periphery of her right eye. The left eye was enucleated. Histology confirmed the presence of a choroidal melanoma of the mixed type. After 3 1/2 years with regular follow-ups growth of the asymptomatic tumour was noticed. The fast growth was accompanied by a haemorrhage in the vitreous and a secondary retinal detachment. External radiation with a dose of 33.6 Gy resulted in a regression of the tumour, improvement of visual acuity to 0.5 and re-attachment of the retina, lasting the remaining 8 months of life. Multiple metastasis to the liver caused her death.