The tumor necrosis factor receptor 2 (TNFR2) gene localizes to 1p36. 2, a genomic region characteristically deleted in neuroblastomas and other malignancies. In addition, TNFR2 is the principal mediator of the effects of TNF on cellular immunity, and it may cooperate with TNFR1 in the killing of nonlymphoid cells. Therefore, we undertook an analysis of the genomic structure and precise physical mapping of this gene. The TNFR2 gene is contained on 10 exons that span 26 kb. Most of the functional domains of TNFR2 are encoded by separate exons, and each of the repeats of the extracellular cysteine-rich domain is interrupted by an intron. The genomic structure reveals a close relationship to TNFR1, another member of the TNFR superfamily. Based on electrophoretic analysis of yeast artificial chromosomes, TNFR2 maps within 400 kb of the genetic marker D1S434. In addition, we have identified a new polymorphic dinucleotide repeat within intron 4 of TNFR2. The genetic sequence information and exon-intron boundaries we have determined will facilitate mutational analysis of this gene to determine its potential role in neuroblastoma, as well as in other cancers with characteristic deletions or rearrangements of 1p36.