Polyneuropathy, organomegaly, endocrinopathy, M-protein, and skin changes (POEMS) syndrome is a paraneoplastic syndrome due to an underlying plasma cell neoplasm. The diagnosis of POEMS syndrome is made with three of the major criteria, two of which must include polyradiculoneuropathy and clonal plasma (PCD), and at least one of the minor criteria. The most frequent liver manifestation is hepatomegaly. Idiopathic portal hypertension (IPH) has been reported rarely in POEMS syndrome. The precise etiopathogenesis of IPH is not fully elucidated. We report a 46-year-old male patient presenting with POEMS syndrome. He presented postprandial vomiting and left tinnitus. Loss of appetite, leanness, and excessive sweat were concomitant symptoms. Abdominal examination revealed splenomegaly and an absence of hepatomegaly. Abdominal ultrasonography was therefore performed, revealing hepatosplenomegaly with dilatation of the splenic vein. An abdominal computed tomography confirmed the presence of an 18.5 cm splenomegaly with dilatation of the splenic and portal vein. Upper endoscopy with biopsy showed minimal, non-atrophic, mildly active chronic, follicular antrofundic gastritis without esophageal varices. Laboratory and radiological examinations could not confirm the etiology of portal hypertension. The liver biopsy suggested hepatoportal sclerosis, compatible with IPH. The patient initially received six courses of the CTD (cyclophosphamide, thalidomide, and dexamethasone) protocol. He subsequently proceeded to an autologous stem cell transplant (ASCT), and the patient achieved a considerable improvement. POEMS syndrome could be complicated with IPH. There are only a few cases of IPH associated with POEMS syndrome in the literature. This case highlights the manifestation of portal hypertension in POEMS syndrome.