OBJECTIVES: The aim of the project was the assessment of clinical usefulness of the determination of blood serum homocysteine concentration, folic acid and vitamin B-12 in recurrent miscarriages. METHODS: 30 non-pregnant women with recurrent miscarriages (examined group - I) and for 20 non-pregnant women without obstetric failures in medical history (control group-II) were examined. RESULTS: In the examined group (group I), the average concentration of homocysteine (9,45 mu mol/1) was not statistically higher in comparison to the control group (group II) (8,47 mu mol/1) (p > 0,05). In group I the average vitamin B-12 concentration in blood serum was 178,3pg/ml and it was statistically lower (p < 0,001) in comparison he with the control group (II) (268,6pg/ml). Such a relation was not observed for t vitamin where the average concentration of this parameter was not dependant on the miscarriage number. A high negative correlation (R= -0,5397, p < 0,01) was observed between the level of folic acid and homocysteine concentration in the group in t the average concentration of vitamin B-12 in blood serum and the average homocysteine in the nullipara group with recurrent miscarriages. CONCLUSIONS: Together with the increasing number of abortions, the average homocysteine concentrations grew and the average folic acid concentrations lowered.