Melanomas are tumors originating from melanoblast and melanocyte cells. They are commonly seen in the skin, eye and oral cavity respectively in cats. Ocular melanomas are named as epibulbar (limbal), conjunctival and uveal depending on the location of the eye. In cats, iridial melanomas develop mostly from the anterior uvea (iris and ciliary body) and rarely from the posterior uvea (choroid). This case was a 16-year-old male cat who was brought to the hospital with complaints of redness, pain and enlargement of the eyeball for a long time. Ophthalmologic examination revealed blepharospasm, ocular pain, episcleral congestion, corneal vascularization and diffuse edema. The size, localization and extent of the mass were determined by ocular ultrasound and magnetic resonance imaging (MRI) findings. Primary intraocular malignant melanoma was diagnosed by histopathological examination of the eye removed by enucleation method. No metastasis was observed in the postoperative period of one year. In this case, we aimed to share ophthalmologic, ultrasonographic, magnetic resonance imaging, histopathological examination findings and treatment and prognosis of primary intraocular malignant melanoma.