Familial occurrence of Wolff-Parkinson-White (WPW) syndrome is uncommon and to date only seven instances have been documented in the literature. We describe another unusual family in which the proband, his father and two of his five brothers (including one who died suddenly) showed WPW conduction. A younger sister showed evidence of Lown-Ganong-Levin (LGL) pre-excitation. This pedigree is consistent with autosomal dominant inheritance and supports the importance of testing asymptomatic family members of patients with WPW because it is a potentially life-threatening conduction disorder.