Pelvic lipomatosis is an uncommon disease with no clear etiology and it occurs secondary to deposition of a large amount of fatty tissue in the pelvis. This deposition causes compression to the rectum, bladder, and venous structures. Because of this compression, various symptoms, such as recurrent urinary infections, dysuria, tenesmus, and constipation, have mostly been reported. However, iliac or superior vena cava thrombosis secondary to vascular compression of pelvic lipomatosis is rare. This report describes a case of pelvic lipomatosis, which was associated with right-sided mild hydronephrosis and portal vein thrombosis.