Background: Epithelial ovarian carcinomas are one of the most common causes of death among gynecologic malignancies in the Czech population. This group of tumors is characterized by considerable heterogeneity in terms of its pathogenesis and response to therapy. It is questionable whether advances in the elucidation of molecular pathogenesis of various types of epithelial ovarian carcinomas can contribute to application of personalized targeted therapy. Aims: This work aims to summarize current knowledge on carcinogenesis and molecular basis of epithelial ovarian cancers and point out their potential applications in clinical practice. The characterization of the epithelial ovarian carcinomas is based on a dualistic model, which divides these tumors into two groups based on their different origins and mechanisms of carcinogenesis. Type I includes low-grade serous carcinomas, endometrioid carcinomas, mucinous carcinomas and Brenner tumor. Type II then comprises high-grade serous carcinomas. Conclusion: The new findings acquired by next generation sequencing revealed major differences in the genetic alterations in both groups of tumors. Differences in genetic instability between the two groups of tumors determine the mechanisms of their carcinogenesis and show new ways for application of targeted therapy. Deficient homologous recombination and high genetic instability in type II tumors is a prerequisite for efficient application of platinum cytostatics and PARP (poly-ADP ribose polymerase) inhibitors. On the other hand, carcinogenesis of the less aggressive, but often resistant type I tumous is dependent on the activation of signaling pathways PI3K/AKT and RAS/BRAF/MEK/ERK pathway. Targeted inhibition of these pathways could efficiently improve therapy of type I tumors and decrease serious adverse side effects.