Background: Early pregnancy loss is defined as the termination of pregnancy before 20 weeks' gestation or with a fetal weight of <500 g. Of those that are recognized, 15-20% result in spontaneous abortions (SABs) or ectopic pregnancies. Approximately 5% of couples trying to conceive have two consecutive miscarriages, and approximately 1% of couples have three or more consecutive early pregnancy loss. Increased levels of homocysteine may be due to inadequate dietary intake of folate and vitamin B12 and inherited defects within the methionine-hmocysteine pathway such as MTHFR c677T gene polymorphism. Hyperhomocysteinemia is associated with the syndromes of repeated miscarriage. Objective: The aim of the current study is to estimate the serum levels of Homocystine and vitamin B12 and their relation to prevalence of recurrent spontaneous abortion in pregnancies with history of recurrent miscarriage. Subjects and Methods: In this study 80 pregnant women classified into two groups: GroupI:60 consecutive pregnant women who had suffered from two or more miscarriages, and Group II: 20 pregnant women with no history of abortion .The following estimations were done (for each woman in the study): serum homocysteine and vitaminB12 were estimated  using  ELISA technique. Results: Results showed a significant increase in serum level of homocysteine in the first group compared to control group(p<0.0001) and a  low serum level of vitamin B12 which was significantly decreased in the study group (group 1) compared to control group(p<0.0001). Moreover, Our results showed a negative correlation between homocysteine and vitamin B12. Conclusion: The elevated serum homocysteine levels during pregnancy were significantly associated with recurrent pregnancy losses. Moreover, reduced serum vitamin B12 level was considered a   risk for recurrent miscarriage. Homocysteine is most sensitive and specific
parameters in the  recurrent pregnancy losses.