Over 50% of RPL cases are with unknown etiologies. Recurrent Pregnancy Loss affects around 5% of pregnant women. The effect of PD-1.1, PD-1.3, and PD-1.5 polymorphisms on the risk of RPL in the Palestinian population has not been explored before. The above mensioned genotypes are expected to be associated with increased risk of Recurrent Pregnancy Loss or, the opposite, could protect against miscarriage. The prevalence of such polymorphisms will be determined in women suffering from RPL in Gaza strip in this work.