Background: Placenta growth factor is, VEGF family member, a Pleiotropic Factor affects a variety of cell types and regulates various biological responses. PlGF is similar in structure and function to VEGF, and it amplifies VEGF's angiogenic actions. Ovulation stimulation during cycles of in vitro fertilization (IVF) for the mangment of infertility results in ovarian hyperstimulation syndrome (OHSS), an iatrogenic side effect. Considering potential roles of PlGF and its receptor (sflt-1) in angiogenesis, the association of these factors with OHSS among study women during controlled ovarian stimulation have evaluated in the present study. Methods: comparative cross sectional study including of 60 women who go through controlled ovarian stimulation. On oocyte retrieval day, their serum and follicular fluid were taken. The concentrations of PlGF and sFlt-1 were assessed using ELISA. Results: Eighteen patients presented with ovarian hyperstimulation syndrome (OHSS) and 42 patients were no OHSS. There was significantly higher serum PIGF in women with OHSS patients as compared to women with no OHSS, 141.4 ± 11.8 versus 91.9 ± 5.4 respectively (p<0.001). Furthermore Follicular fluid PlGF there was significantly higher in women with OHSS patients as compared to women with no OHSS, 163.4 ± 7.2 versus 91.1 ± 5.5 respectively (p<0.001).additionally Follicular fluids PlGF/sFlt ratio significantly higher in women with OHSS patients as compared to women with no OHSS, 0.034 ± 0.01 versus 0.026 ± 0.01 respectively (p<0.001). On the contrary there was significantly lower serum and follicular fluid sFlt in ovarian hyper-stimulated patients Conclusions: These statistics show that serum and FF PlGF and PlGF to sFlt ratio higher in women with ovarian hyperstimulation syndrome (OHSS) patients as compared to women with no OHSS. So the PlGF may be played an important a role in angiogenesis dysregulation.