Septic thrombophlebitis of the portal venous system, also known as pylephlebitis, is a rare clinical condition with nonspecific clinical presentation, in which imaging has a crucial role in its prompt diagnosis. We report a case of a 13-year-old male who presented with fever, jaundice and hepatomegaly. Ultrasound and computed tomography revealed portal vein thrombosis, hepatomegaly, splenomegaly, and mild ascites. No primary focus of infection, underlying thrombophilia or malignancy was identified, and broad-spectrum antibiotic therapy and anticoagulation were initiated, resulting in clinical improvement and partial recanalization of the portal vein. Clinical and imaging follow-up should be maintained to exclude the development of portal hypertension.