Abstract: The discovery that hyperhomocysteinemia may be responsible for several pregnacy complications has only recently been made. With this study, it is aimed to determine levels of homocysteine in pregnant women encountered with abortus imminens, abortus incompletus and abortus. In the study in 35 abortus imminens, 36 abortus incompletus, 30 abortus missed and 33 healthy pregnant women, homocysteine levels are specified by making use of competitive immunoassay technique. Homocysteine levels were determined in the abortus imminens group as 8.78±5.29 μmol L-1 in the abortus incompletus group as 10.55±4.49 μmol L-1, in abortus missed group as 9.03±4.29 μmol L-1 and as 4.87±1.27 μmol L-1 in the control group. Homocysteine levels were found to be excessively high with all abortus groups when compared to the control group (p<0.0001). The homocysteine levels of pregnant individuals using folic acid (7.354±3.78 μmol L-1) in comparison to those not using (9.58±5.27 μmol L-1) was determined as significantly low (p<0.01). As a result of this study, it cannot be explained that all abortus develop in parallel with hyperhomocysteinemia. However, hyperhomocysteinemia is together with an increased risk of abortus and such a risk might possibly be reduced with use of folic acid, it should definitely be recommended to use folic acid.