Aseptic abscesses (AAs) are extraintestinal manifestations of inflammatory bowel disease (IBD). IBD-associated AAs are rare in Japan. We treated a 45-year-old man with ulcerative colitis (UC)-associated AAs. During remission, multiple progressive abscesses were detected in the spleen; he underwent splenectomy because an infectious disease was suspected. Although his condition improved temporarily after splenectomy, a large liver abscess was noted, and a diagnosis of UC-associated AAs was made. Granulocytapheresis (GCAP) and infliximab (IFX) administration resolved the abscess. This is the first reported case of UC-associated AAs in a Japanese patient treated by splenectomy, GCAP, and IFX.