Pseudoaneurysm of the splenic vein is a rare entity which is associated with pancreatitis in 52 % cases. Pseudocysts of the pancreas create approximately 70 % of all cystic lesions of the pancreas. One of the most dangerous complications of pancreatic pseudocysts is bleeding into the cystic lumen. This is caused by perforation of the pseudoaneurysm of the splenic vein. Enzymatic damage of the splenic vein´s wall is the cause of pseudoaneurysm. The clinical condition varies. It can be asymptomatic or bring about haemodynamic instability. The diagnostic process of pseudoaneurysm of the splenic vein is difficult. This case study introduces a case of a 50‑year‑old man with the anamnesis of recurrent pancreatitis caused by alcoholism. He had abdominal pain and was diagnosed with a pseudocyst of the pancreas. Abdominal CT showed an extensive capsulated collection in the left subphrenic space, 23cm in diameter, with serosanguineous content and coagulations. The CT visualised the mass effect on the surrounding tissues and a complete deformation of the spleen. Between the collection and partially oppressed tail of the pancreas there was a venous pseudoaneurysm, 3.5cm in diameter. Considering its localization, it most probably originated from the splenic vein. Surgery was done. We did distal resection of the pancreas with a complete removal of the pseudocyst and spleen (Fig. 7, Ref. 11). Keywords: splenic vein, pseudoaneurysm, pancreatitis, pancreatic pseudocysts.