Genetic factors may influence the timing of menopause. Premature ovarian failure (POF) has recently been identified as a genetic entity, but no genetic data are available on early menopause (EM). We investigated 36 patients with EM (age of menopause between 40 and 45 years of age) using cytogenetic and pedigree analysis. In 30 patients of this study the EM was idiopathic and 15 subjects (50%) had a familial condition of EM or POF. Pedigree analysis revealed a dominant pattern of inheritance of EM through maternal or paternal relatives. Our data reveal that POF and EM patients show the same genetic features and we postulate that these conditions may be a variable expression of the same genetic disease.