The histopathological classification of ovarian surface epithelial carcinomas (referred to hereafter as ‘ovarian carcinoma’) has shifted over the past 10 years to reflect more clearly our understanding of molecular events during carcinogenesis. Ovarian carcinoma is no longer viewed as a single entity but as multiple disease processes, with each having different molecular pathways altered during oncogenesis, resulting in differences in clinical and pathological features, such as biomarker expression, pattern of spread and response to chemotherapy. There are five subtypes of ovarian carcinoma that are sufficiently distinct and well-characterized that they should be considered to be different diseases, i.e. high-grade serous, clear cell, endometrioid, mucinous and low-grade serous, from most to least common, respectively. This review summarizes the molecular abnormalities of these five ovarian carcinoma subtypes, relating them to clinical and pathological features.