Palindromic rheumatism is very rare in children. The familial occurrence of the disease has been only briefly reported previously. A family is described here in which the mother and her 3 children suffered from typical palindromic rheumatism, which ran a benign course. All 4 members were seronegative and the HLA types of the children were identical. The HLA genotype of the mother was HLA A2, Cw4, Bw41, Bw6, DR5, MT2/Aw32, CX, Bw44, Bw4, DR1, MT1. HLA DR5 has previously been found to be associated with juvenile rheumatoid arthritis, while DR1 in Jews is significantly associated with adult-onset rheumatoid arthritis. DR5 was shared by the mother and her 3 children. The presence of the antigen DR5 in this sibship suggests that palindromic rheumatism may be a variant of juvenile rheumatoid arthritis with a relatively late onset and a more benign course. Tissue typing of patients with palindromic rheumatism may give a clue to prognosis. The patients' youth and the familial involvement, with identical HLA characteristics, are the outstanding features of this family.