Developments in a new system of brachytherapy for tumours of the eye are reported. This involves the use of 125I sources with special screens and filters to avoid irradiation of vital structures and to produce a homogeneous radiation field. Methods for the treatment of tumours of the lids, conjunctiva, retina, choroid and lachrymal gland have been developed. Sixteen out of 20 treatments appear to have been successful. This system would seem to be a material advance on those previously reported.