22 patients with extending intraocular lesions are examined by serial computed tomography after a bolus injection of contrast medium. The changes of X-ray density of the tumor areas are compared with those of the vitreum and of brain tissue. Choroidal melanomas exceeding 2 mm in prominence are identified as highly vascularized areas in which contrast enhancement according to certain brain tumors takes place. A differentiation from large pseudotumors seems to be possible. The value of this method for the differential diagnosis of choroidal melanomas is discussed.