Palmoplantar hyperhidrosis (PPH) is a disorder characterized by excessive sweating of the palmar surfaces of the hands and feet due to emotional sweating. There have been reports based on family histories, and the involvement of genetic factors has been suggested. Among 410 PPH patients who visited our hospital from August 2006 to October 2008, onset age and family history were investigated in order to prepare pedigree charts, and family histories were confirmed in 147 patients (36%). Between the family history and negative family history (sporadic) groups, no significant differences were seen in onset age, sex or sweat volume. With regard to the patterns of incidence within families, parent-child was the most common at 58%, followed by sibling cases at 18%. The incidence of PPH in three generations was 13%. Pedigree charts prepared based on data obtained by patient interviews suggested autosomal dominant inheritance.