Over the last 10 years, patient-derived tumor organoids (PDTOs) have significantly expanded the range of preclinical models and gradually transformed the landscape of three-dimensional cell culture in cancer research. PDTOs can be efficiently generated from patient tumor samples and accurately reproduce the histological and molecular features of the original tumor. As a result, PDTOs represent powerful tools for oncology research, and their potential application in clinical settings holds great promise for advancing precision medicine in cancer treatment. In this chapter, we present a comprehensive overview of the techniques used for organoid growth, important elements for the preservation of tumor heterogeneity, the assays that can be implemented, the current organoid biobanks and extending to the discovery of novel therapeutic targets, preclinical testing of new anticancer agents, and advancements in precision medicine. Ongoing technological advancements and the development of autologous coculture systems for PDTOs aim to address current challenges and fully harness the potential of these models. Integrating PDTOs as routine tools in clinical oncology could pave the way for a new era of precision cancer care in the next decade.