Hydrocephalus is an anomaly caused by an excessive accumulation of cerebrospinal fluid in the ventricular system of the brain and/or subarachnoid space. It leads to neurological disorders in humans and animals. Prenatal injuries, such as viral infections or drug intoxications, may cause congenital hydrocephalus in cats. Moreover, a dry form of feline infectious peritonitis (FIP), toxoplasmosis or some brain neoplasms (e.g. ependymoma) may lead to the development of acquired hydrocephalus in cats. In this report the authors describe a case of a 5-month-old Burmese cat with incontinence and a plantigrade posture as leading symptoms of acquired hydrocephalus. Hydrocephalus was diagnosed using the magnetic resonance imaging (MRI) technique. Moreover, inflammatory foci were detected in the medulla oblongata, whereas a cerebrospinal fluid analysis revealed lymphocytic pleocytosis and an increased protein concentration. These clinicopathological findings are typical of the neurological form of the dry FIP. The cat was euthanized because the hydrocephalus was inflammatory and its cause was most probably infectious. This case report shows the practical use of MRI in veterinary practice.