Typing of the sixth component of complement (C6) was performed on serum samples from 167 unrelated Norwegian Lapps. The following allele frequencies were found: C6A, 0.53 and C6B, 0.47. The phenotype distribution was in good agreement with Hardy-Weinberg expectations. Variant phenotypes were not observed. A preliminary material of 1,623 non-Lappish Norwegians showed the following allele frequencies: C6A, 0.59 and C6B, 0.41. The difference in allele distribution between the two materials was statistically significant.