Plasma samples from patients with various types of von Willebrand's disease were subdivided into six patterns according to the electrophoretic mobility and shape of VIIIR: Ag on crossed immunoelectrophoresis (CIE): pattern 1 no precipitation are, pattern 2 normal mobility with low arc, arc, pattern 3 intermediate mobility with low arc, pattern 4 faster anodal mobility with low arc, pattern 5 normal mobility with normal are height, pattern 6 faster anodal mobility with normal are height. Of 62 patients, 14 had pattern 1, 6 pattern 2, 16 pattern 3, 12 pattern 4, 9 pattern 5, and 5 pattern 6. Large pore polyacrylamide-agarose gel-crossed immunoelectrophoresis (PAAG-CIE) of crude factor VIII fraction from cryoprecipitate revealed no arcs in patients with pattern 1, three arcs of reduced height in the patients with patterns 2 and 3, four arcs very similar to normal control in patients with pattern 5, and two arcs with fast anodal migration in the patients with patterns 4 and 6. Crude factor VIII fractions from normal cryosupernatant showed one low fast anodally migrating arc corresponding to the fourth arc of normal cryoprecipitate. No peak was seen in patients with pattern 1, and one low fast anodal arc similar to normal control was present in the patients with patterns 2, 3, 4, 5 and 6.