Objective: To examine the localization of vascular endothelial growth factor receptors (VEGF-R) and the changes in VEGF-R messenger ribonucleic acid (mRNA) expression in various regions of the oviduct from fertile women throughout the ovulatory cycle. Design: Prospective observational study. Setting: University-based obstetrics and gynecology department. Patient(s): Twenty-two women who underwent laparoscopic tubal sterilization or hysterectomy for a benign gynecological condition. Intervention(s): The mucosal layer was isolated from the oviduct tissue. Immunohistochemistry and a semiquantitative reverse-transcriptase-polymerase chain reaction (RT-PCR) was performed. Main Outcome Measure(s): Immunohistochemical localization of VEGF-R proteins in oviduct tissue, and the differences of VEGF-R mRNA expression in the various regions of the oviduct and in the various stages of the ovulatory cycle. Result(s): Immunohistochemical study localized VEGF-R, both KDR and flt-1, in the oviduct luminal epithelium, smooth muscle cells as well as blood vessels within the oviduct. Messenger RNA expression of KDR, but not flt-1, was significantly higher in the ampullary and infundibular regions than in the isthmus. Messenger RNA expression of flt-1, but not KDR, varied significantly in the oviduct along the course of an ovulatory cycle, with the highest level in the periovulatory stage. Conclusion(s): These results suggest that the two VEGF receptors may have different roles in the oviduct. Our data support a role for KDR in oviduct angiogenesis whereas flt-1 appears to be important in the temporal regulation of oviductal secretion. (C)2004 by American Society for Reproductive Medicine.