Precursor B-cell lymphoblastic lymphoma (B-LBL) is an uncommon subtype of Non-Hodgkin lymphoma (NHL), accounting for only 0.3% of NHL in adults and less than 10% of all LBL cases. Unlike T-cell LBL, it usually presents with extranodal involvement while sparing the bone marrow (BM). Among the 27 patients with LBL treated in the Asan Medical Center between January 2007 and March 2012, 3 had B-LBL. All had a good performance status and low International Prognostic Index. However, unlike most previously reported cases, the patients had lymphoma in their bone marrow and extranodal sites such as bone and lung. After intensive combination chemotherapy, one patient achieved a complete response and the other 2 patients, a partial response. Our experience suggests that multiple extranodal sites may be involved in B-LBL and BM involvement may not be as infrequent as previously thought. Furthermore, intensive chemotherapy seems to be effective.