The surface membrane antigens of 7 neuroblastoma and 91 leukemia-lymphoma cell lines were studied with the use of a total of 36 murine monoclonal antibodies (MoAb) primarily developed against hematopoietic cells and 2 MoAb developed against human fetal brain. Five of the MoAb against hematopoietic cells (BA-1, BA-2, DU-ALL-1, J-5, and BA-3) consistently bound to common acute lymphoblastic leukemia cell lines, and 2 others (MCS-2 and OKM-1) reacted uniformly with acute myeloblastic-acute monoblastic leukemia cell lines. However, these 7 MoAb also reacted with 1-7 neuroblastoma cell lines. All the human neuroblastoma cell lines bound MoAb BA-2 and DU-ALL-1. Six of the 7 lines reacted with BA-1. Only 1 neuroblastoma cell line (SJ-N-CG) gave positive staining with J-5 and BA-3, and another line (SK-N-AS) bound MoAb MCS-2 and OKM-1. Anti-fetal brain MoAb (UJ-13A and UJ-127-11) were highly positive for all the neuroblastoma cell lines. By contrast, 4 of 43 leukemia-lymphoma cell lines tested bound these anti-fetal brain antibodies. Both B3/25 and OKT-9, anti-transferrin receptor antibodies, reacted with all of the hematopoietic and neuroblastoma cell lines. These results demonstrate that neuroblastoma and hematopoietic cell lines possess common antigenic determinants despite their different embryologic origins. The neuroblastoma cell lines may be classified into subgroups on the basis of phenotype profiles determined by the MoAb. MoAb may be useful in characterization and classification of neuroblastoma cells, as has already proved to be the case for cells of the hematopoietic lineages.