Our aim was to relate vaginal candidiasis to vaginal oestrogenisation. First, the incidence was determined (subjected to chi-square analysis) of vaginal Candida albicans infection in 339 consecutive dermogynaecology clinic patients aged 55 years and over, of whom 142 were using and 197 were not using oestrogen. Second, the ability of Candida species to utilise glycogen as a sole nutrient source was studied by performing assimilation tests using yeast nitrogen broth as a basal medium. infection on initial presentation compared with 4% in the cohort not using oestrogen (p < 0.001). All 34 isolates of C. albicans assimilated glycogen. Twenty-six non-albicans species of Candida tested did not assimilate glycogen. In this study of postmenopausal women, there was a highly significant relationship between the usage of oestrogen and the occurrence of C. albicans infection. The production of glycogen by oestrogen stimulated epithelial maturation provides an attractive substrate for C. albicans.