Case summary Ventriculoperitoneal shunt placement is the most commonly utilised surgical treatment for hydrocephalus in human and veterinary patients. Migration of the peritoneal catheter is an uncommon but well-documented complication in people, usually occurring within the first 3 months postoperatively, although only a single feline case report exists. A ventriculoperitoneal shunt was placed in a domestic shorthair cat, aged 4 years and 10 months, following a diagnosis, with MRI, of unilateral, non-communicating hydrocephalus. Diarrhoea, increased vocalisation and pruritus were reported within the first 3 months postoperatively. A shunt-associated seroma developed, which was aspirated under ultrasound guidance. Within 3 days, the entire peritoneal catheter was subcutaneously coiled at the level of the seroma. The peritoneal catheter was replaced within the abdomen via a new subcutaneous tunnel. No further complications had occurred 24 months following revision surgery. Relevance and novel information This is the second report describing peritoneal catheter migration in a cat. Repetitive head and neck movements during self-grooming, raised intra-abdominal pressure secondary to vocalisation and tenesmus, and negative pressure exerted during seroma aspiration may have contributed to ventriculoperitoneal shunt migration. Excessive loose skin and increased activity may further increase the risk of migration in cats. Diagnostic imaging should be offered prior to and following aspiration of shunt-associated swellings, and minimal negative pressure should be exerted. Attempts to reduce the frequency of postoperative self-grooming, prevention and prompt treatment of conditions predisposing to raised intra-abdominal pressure and moderate exercise restriction, particularly within the first 3 months, may help reduce the risk of peritoneal catheter migration.