In 43 patients with pauciarticular and 26 patients with polyarticular juvenile chronic arthritis (JCA), an increased frequency was found for HLA-B27 (36%) in male patients with onset of the disease over 9 years of age. The antigen "DRw6" was observed in high frequency (average 57%) in all subtypes of the disease. Indications for increased frequencies were obtained for DR3 in male JCA (40%) and DR5 (42%) in female JCA patients.