Portal vein thrombosis (PVT) following sleeve gastrectomy is rare. There are limited documented cases within the literature. The presentation of PVT varies on a spectrum from mild non-specific abdominal symptoms to life endangering clinical emergencies. This is the case of a 58-year-old woman who presented to the surgical assessment unit with acute onset abdominal pain 2 weeks post laparoscopic sleeve gastrectomy for morbid obesity. The initial diagnosis was that of a gastric sleeve leak. The patient deteriorated clinically and underwent a CT scan of her abdomen. This revealed the presence of an acute thrombus filling the portal vein with extension into the superior mesenteric vein branches. There were radiological changes suggestive of acute small bowel ischaemia. The patient underwent a laparotomy in theatre and 50 cm of the necrotic small bowel was resected. Postoperative care was carried out in the intensive care unit for 15 days.