Urokinase type plasminogen activator(uPA) plays important role in invasion and metastasis of cancer. Its actions are activated and amplified by a specific cell-surface receptor (urokinase type plasminogen activator receptor: uPAR). The present study was undertaken to determine the importance of the uPAR for migration and invasion of cancer cells through immunohistochemical localization of uPAR. HEp3 cells were cultured in monolayer and suspended, then they were stained by immunofluorescence, APAAP(alkaline phosphatase anti-alkaline phosphatase) and immunoperoxidase method. The receptor(uPAR) was found to be located at cellular contact sites. In suspension uPAR staining of HEp3 cells showed focal distribution. In vivo model of invasion, the uPAR was localized on leading edge of tumor of cholioallatoic membrane(CAM) inoculated with HEp3 cells. This suggests that uPAR might play crucial role in migration and invasion of cancer cells through mediating proteolysis at cellular contact sites especially in leading edge of the tumor.