A ‘new’ Lutheran-related antibody, named anti-Lu14, reacts with approximately 2.4% of random bloods. Red cells of the rare Lu:-8 phenotype are Lu: 14. The data indicate, with a high probability, that the Lu 14 antigen is a product of an allele of Lu^8 and that Lu^14 and Lus comprise a third pair of alleles at the Lutheran locus. Red cells of the original Sw (a+) propositus are Lu: 14. By coincidence, he has inherited two low-incidence genes. This observation may explain the discrepancy in different families concerning a possible relationship between Sw^a and Lutheran. Pedigree information now suggests that Sw^a is not a Lutheran gene.