Portal and splenic vein thrombosis are uncommon, potentially fatal post-operative complications following splenectomy. These thrombotic events may be asymptomatic or present with non-specific symptoms. Therefore, imaging is important for diagnosis. The risk of thrombosis is linked to spleen size, pre-operative thrombocytopenia and surgical technique. We present the case of a 40-year-old man who underwent curative and diagnostic laparotomic splenectomy following chronic thrombocytopenia and concurrent splenomegaly who subsequently developed extensive portal and splenic vein thrombosis. Teaching Point: Portal and splenic vein thrombosis after splenectomy is a relatively uncommon but important diagnosis in which radiology has a pivotal role.