Fabry disease is an X linked lysosomal storage disorder resulting from deficiency of α-galactosidase A activity. Although disease manifestations in heterozygous females with Fabry disease have been considered to be rare and mild, heterozygous patients with severe symptoms have recently been reported. In this study we focused on the clinical characteristics of Japanese females patients with Fabry disease and analysed data from 36 women. Data on clinical manifestations such as acroparaesthesia, hypohidrosis, angiokeratoma, corneal opacities, proteinuria, end-stage renal disease (ESRD), left ventricular hypertrophy (LVH) and cerebral infarction were obtained by questionnaire; these analysed by the Kaplan-Meier method and compared with the data from Japanese male patients. Eighty-six per cent of female patients had at least one clinical sign of Fabry disease. Their most common symptoms were acroparaesthesia and corneal opacities, and diagnosis was most commonly based on family history. The cumulative incidences of angiokeratoma, corneal opacities, proteinuria, ESRD, LVH and cerebral infarction were significantly lower in female than in male patients. However, corneal opacities, proteinuria and LVH developed progressively in female patients as well as in male patients. The incidence of LVH was especially high in older female patients and the cumulative incidence of LVH in women over 68 years of age was 100%. We consider that the term X-linked 'recessive' is inappropriate for Fabry disease because of the high prevalence of its pathognomonic signs in heterozygous female patients. Careful and long-term evaluation of clinical signs is important in heterozygous females patients with Fabry disease.