Objective: This study aimed to explore the risk of abnormal cervical cytology in relation to serum folate and vitamin B12 levels, and demographic characteristics. Patients and Methods: A case-control study was carried out among women attending the gyne­cology clinic for cervical cytology screening. At the follow-up clinic visit, fasting blood samples were collected from 103 cases with abnormal cervical cytology of the cervix and 175 controls with cytological normal smears and serum folate and vitamin B 12 levels were measured. Data from cases and controls were compared. Logistic regression analysis was used to estimate the relative odds of abnormal cytology with increasing vitamin B12 levels. Results: There were no significant differences between cases and controls in demographic characteristics and mean folate levels (p > 0.05). The mean vitamin B 12 level of cases was significantly lower than that of controls (p < 0.001). Dichotomized logistic regression analyses of vitamin B12 levels were significantly different(p <0.001). The predicted percentages at a cut-off value of 0.5 were as follows: sensitivity 70.0%, specificity 74.6%, positive predictive value 71.8% and negative predictive value 72.6%. The logistic regression analysis of the 1st and the 4th quartiles of vitamin B12 levels showed a significant difference p < 0.001, OR: 1.525 (CI, 1.175-1.875). Conclusion: The results of this study suggest that lower vitamin B12 levels are associated with abnormal cervical cytology. It is recommended that women should consume not only folate-rich foods such as fruits and vegetables but also vitamin B12-rich foods such as meat, fish, milk products and eggs in a balanced way.