Lymph node metastasis through the lymphatic vessels is a critical step in determining the outcome of ovarian cancer patients, and prognosis should be improved by preventing lymph node metastasis. However, experimental models for lymph node metastasis of ovarian carcinoma are not available. We developed an orthotopic transplantation model to study this process in nude mice using the human ovarian carcinoma cell lines, KF and MH. Highly metastatic sublines (KF-LN3 and MH-LN3) were selected in vivo in nude mice by repeated orthotopic transplantation, lymph node metastasis formation and culturing the tumour cells in vitro. Because this model seems to correspond to the advanced clinical stage of ovarian carcinomas, it should be useful in understanding the molecular biology of ovarian carcinomas and in the development of therapeutic modalities against lymph node metastasis.