Chromosomal translocations involving the immunoglobulin (IG ) loci are frequently seen in most subtypes of B-cell malignancy and have both diagnostic and prognostic utility. These translocations can be detected in clinical samples by several techniques including metaphase cytogenetics, interphase fluorescent in situ hybridization, and a variety of PCR methods; interphase FISH is the most commonly used clinical method. Although all the common IG translocations have been identified and cloned, new IG translocations continue to be identified in both B-cell leukemia and lymphoma. It remains important to identify the involved target genes since they define novel pathogenetic drivers of disease and may represent novel therapeutic targets. This brief chapter outlines methods of detection of chromosomal translocations involving the IGHJ segments using long distance inverse (LDI) PCR and their application to clinical lymphoma samples.