The objectives were to evaluate the beneficial effect of intra-operative echographic plaque site localization and to assess the rate of complications of postplaque insertion. This paper is a descriptive study of 48 patients with choroidal melanoma who underwent iodine-125 (I(125)) or ruthenium-106 (Ru(106)) plaque radiotherapy with intra-operative echographic confirmation of plaque placement with the aid of a nonradioactive plaque (dummy) at McGill University Health Centre from 1997 to 2003. Patients' mean age was 63.7 years; 52% (25/48) male, 48% (23/48) female. Twenty-seven percent (13/48) of the tumors were confined to the right eye and 73% (35/48) to the left eye. Forty-eight percent (23/48) of the tumors were located posterior to the equator, 14.6% (7/48) were anterior to the equator, 18.7% (9/48) in posterior pole, and 18.7% (9/48) at equator. Sixty-nine percent (33/48) received I(125) and 31% (15/48) had Ru(106) treatment. Ninety percent of the dummy plaques were initially positioned suboptimally and required repositioning under echographic guidance. At mean follow-up of 18.8 months, there was no tumor-related death or metastasis, but one patient required enucleation. The dummy plaque technique under echographic visualization resulted in reduction of radioactive exposure time during surgery of up to 50%. Intra-operative echographic utilization has the ability to localize precisely the tumor-plaque relationship, thereby optimizing the radiation delivered to the choroidal melanoma, while minimizing the surgeon's exposure time.