We designed a suction fixation system for the radiosurgical treatment of intraocular malignancies with the Leksell Gamma Knife. Our device consists of a circular suction chamber and an adjustable unit which is fixed to the Leksell stereotactic head frame. All components are made of plastic in order to avoid artifacts in CT or MRI. A permanent suction of 600-800 mbar is provided by a standard vacuum pump, powered by a portable battery. In the Gamma Knife Unit of the Neurosurgical Department at the University of Vienna, we successfully used this device. Up to April 1994 we successfully performed 25 radiosurgical treatments in 12 patients with large or extra-large uveal melanomas and in 1 patient suffering from a choroidal metastasis.