Case summary Two 6-month-old littermate Russian Blue cross kittens presented for megaesophagus, intermittent vomiting and regurgitation. The male kitten was diagnosed with aspiration pneumonia and was suspected to have a hiatal hernia on thoracic radiographs. It presented 1 month later in acute respiratory distress and was euthanized. Post-mortem examination revealed a severe gastroesophageal intussusception with approximately 90% of the stomach inverted into the distal esophagus. Histologic examination confirmed dysautonomia with marked neuronal dropout and degeneration with necrosis, satellitosis of the celiac ganglion and the myenteric and submucosal plexuses throughout the gastrointestinal tract. The less-affected littermate showed improvement on cisapride and was doing well at home at the time of writing. Relevance and novel information Dysautonomia is rare in cats, with only a few reports of affected littermates. Both kittens are significantly younger than the median age previously reported. Detailed descriptions of diagnostic and histopathology findings are included. Gastroesophageal intussusception is a novel complication to consider when managing feline dysautonomia.