Epithelial ovarian cancer comprises several subtypes of tumours that exhibit diverse histopathological features. The intriguing assumption by many epithelial ovarian cancers of specialised features of nonovarian tissue lineages has promoted considerable debate as to whether these tumours arise from the deceptively simple surface epithelium of the ovary. This review focuses on recent molecular and pathological studies of epithelial ovarian cancers that support and challenge their surface-epithelial derivation, and discusses the findings in the context of current views of the 'cell-of-origin' of solid tumours.