We retrospectively evaluated the diagnosis and clinical courses of 8 patients with intravascular large B-cell lymphoma (IVL) diagnosed while they were alive. The median age was 67 years old (range 54 to 82). Most complaints at diagnosis were fever or dyspnea. All patients were in clinical stage IV with B symptoms and 4 patients showed performance status 4. The diagnosis of IVL was confirmed by biopsy specimens from the bone marrow in 4, lung in 2, muscle, adrenal gland, and lymph node in 1 case, respectively. Initial bone marrow involvement was found in 6 patients. Chemotherapy was performed in 7 patients. Rituximab was added to chemotherapy in 5 patients. Though 5 patients are alive at the median follow up of 12.3 months, only 1 patient is in remission. Four of 5 patients treated with Rituximab relapsed. In suspicious cases, it is important to bear IVL in mind and examine bone marrow biopsies for an early diagnosis. In addition, it is suggested that Rituximab may play only a temporary role in the treatment of IVL.