Poor ovarian responders (PORs) are characterized by decreased the response of the ovaries to stimulation. Nowadays, using soft protocol of low doses of Gn with/without oral compounds such as letrozole was accepted as a good option. The endometrium receptive parameters include sub endometrial resistance, pulsatility index and endometrial thickness. Eighty infertile POR women divided to two equal groups and undergoing IVF/ICSI antagonist protocols. One group underwent soft protocol using letrozole 2.5mg twice daily for 5 days starting from cycle day 2-3 overlapped low-dose Gn (225 IU) from cycle day 4-5. Other group received high dose Gn only (450 IU) from cycle day 2-3. Both groups continued stimulation cycle until the day of trigger using the flexible antagonist protocol. Estimation of values of sub endometrial RI and PI with endometrial thickness by 2 Color Doppler ultrasound was performed at day of trigger, OCP and ET. There was no significant difference for endometrial thickness at day of trigger, OCP and ET. There was significant difference in means of sub endometrial RI and PI at day of trigger, OCP and ET (P>0.05). This study showed evidence in favor of soft protocol for POR regarding pregnancy rates in spite of the statically difference in means of sub endometrial RI and PI associated with much less cost effectiveness.