SUMMARYWe have investigated the arrangement of genes in the rare Rh (Rhesus) partial null condition D–, Southern blot and PCR studies under conditions which distinguish the highly homologous RH D and RH C/E genes show that in an Icelandic family with the D– haplotype at least 85% of the RH C/E gene is deleted. This finding is in contrast to one other published case of this phenotype, where intact RH D and C/E genes were found, and also to the full amorph Rhnullphenotype, where an intact RH C/E gene was found, accompanied by the deletion of the RH D gene typical of Rh D‐negative indivi