Elevated thyroid antibodies (AB) have been described in clinically healthy women indicating a postpartum thyroid dysfunction. We evaluated the incidence of the postpartum thyroid dysfunction in Hannover, FRG. 121 women were examined 1-5 days pp and 2-4 months later; 76 were restudied 5-7 months pp. Every time T3, T4, TSH, TBG, microsomal AB and thyroglobulin AB were determined. Six patients showed increased TAB and 10 increased MAB titers. Severe clinical symptoms were not complained. In some patients these elevated titers turned to normal subsequently. Further studies must evaluate the prognosis of this disease.