Twenty-one patients with malignant melanoma of the uvea or iris, some with intra-ocular bleeding, were examined by MRT before and after the administration of Gd/DTPA. In 13 patients, several examinations were performed over a period of 1.5 to 20 months after irradiation of the melanoma. After Gd-DTPA there was an average increase of 13% in the signal intensity from all non-irradiated melanomas (17 cases). Three months following radiation therapy, there was an average increase in signal intensity after Gd-DTPA of 65.7%, and after seven months of 100%. Amelanotic melanomas (two cases) showed a primary increase in intensity of 100%. Two melanomas of the iris were demonstrated by sonography; of these, only one could be shown with certainty by MRT. Small tumours and tumour residues after irradiation were better defined after contrast. In the presence of suspected intra-ocular bleeding, the examination should always be performed after the administration of Gd-DTPA.