Paraneoplastic syndromes involving the visual system are a heterogeneous group of disorders occurring in the setting of systemic malignancy. They are unrelated to local tumor invasion or metastasis and unexplained by nutritional, metabolic, infectious or iatrogenic causes. The presence of antibodies may aid in the diagnosis of a paraneoplastic syndrome, although this is not an absolute requirement. Chorioretinal involvement is seen in CAR (cancer-associated retinopathy) syndrome, MAR (melanoma-associated retinopathy) syndrome, paraneoplastic vitelliform maculopathy, and bilateral diffuse uveal melanocytic proliferation. Paraneoplastic neurological syndromes with ophthalmologic involvement include optic neuropathy, opsoclonus-myoclonus, Eaton-Lambert myasthenic syndrome, paraneoplastic cerebellar degeneration (PCD) and rhombencephalitis.