The BeWo human choriocarcinoma cell line expresses an unusual 41 kDa beta 2-microglobulin-associated class I MHC antigen. HLA-E, -F and -G are known to encode antigens of lower Mr than HLA-A, -B or -C proteins. Using locus-specific probes, we now show that RNA isolated from BeWo cells contains markedly more HLA-G transcripts than peripheral blood lymphocytes (PBL), whilst the converse was noted for HLA-B. These results support recent cloning and sequencing data showing the presence of HLA-G transcripts in BeWo cells.