Background and study aims: During early stages of pregnancy trophoblasts express high amounts of endothelial nitric oxide synthase (eNOS) and consecutively nitric oxide (NO) production in endothelial cells increases, probably playing an important role in implantation, decidualization and regulation of blood flow in the placenta by means of vasodilatation and myometrial relaxation through interaction with the cyclo-oxygenase. Lack of endothelium-derived nitric oxide is associated with the development of endothelial damage, hypertension, coronary spasm, myocardial infarction, coronary artery disease and ischemic stroke. Polymorphism in the eNOS gene was found to be associated with the risk of recurrent abortion. The aim of the study was to determine the association between two common polymorphisms (−786T>C & introns 4) of the endothelial nitric oxide synthase (eNOS) gene with spontaneous recurrent abortion (RSA). Patients and Method: The present study was conducted on a total number of 100 participants, 50 patients with recurrent spontaneous miscarriages and 50 aged matched healthy volunteers women with at least one live birth and no history of pregnancy losas controls. Polymerase chain reaction and restriction fragment length polymorphism analysis (PCR-RFLP) was performed to identify the genotypes. Results: Our results revealed that the frequencies of intron 4 polymorphisms in the patient group were 44.0% for the wild type versus 38% for the heterozygous type and 18% for the polymorphic homozygous type, while in the control group they were 80.0% versus 20.0% for the heterozygous type and 0% for the polymorphic homozygous type. And for the T-786C polymorphism the patient group had 24% for the wild type versus 76% for the heterozygous type and 0% for the polymorphic homozygous type while in the control group they were 70%, 30% and 0% respectively. Conclusion: eNOS polymorphism (in intron 4 and T-786C) was found to be associated with increased risk of RSA, in this sample of Egyptian women. In intron 4, polymorphism ab genotype was more significant in cases associated with RSA, increasing the risk for RSA and aa genotype (homozygous) is present only in cases. While in T-786C polymorphism TC (heterozygous) genotype was more significant in cases of RSA.