The human immunoglobulin lambda (IGL) locus is located on chromosome 22q11.1-q11.2 and contains the genes responsible for the immunoglobulin lambda light chains. This locus was recently mapped (physical map) and its 1-Mb DNA totally sequenced. In this review we focus on the characterization of the v-lambda genes, its chromosomal location, genomics and sequencing of the IGL locus.