OBJECTIVE A high incidence of iron-deficiency is a common observation among adolescent girls, whereas only limited data are available regarding the folic acid status of this group. This study was designed to determine the prevalence of biochemical folic acid deficiency in a group of Turkish adolescent girls. METHODS We surveyed the serum folic acid, complete blood count, and dietary folic acid intake of Turkish adolescent girls after using three-day self-reported food intakes in urban and rural areas of Edirne, Turkey. RESULTS A sample population was composed of 704 adolescent girls; their serum folic acid levels were found to be adequate for 37.6% (> or = 6 ng/mL), marginal for 46% (3 to 5.9 ng/mL), and at deficient levels for 16.3% (< 3 ng/mL). Folic acid deficiencies were found in 20.1% (36 of 179) and 14.7 % (61 of 416) of adolescent girls from rural and urban areas, respectively. Self-reported three-day folic acid intakes were correlated with the corresponding blood values for this nutrient. In the logistic regression analysis, three factors emerged as significant independent predictors of folic acid deficiency: low income (odds ratio [OR]: 2.4, 95% confidence interval [CI]: 1.3-4.2, p < .001), low vitamin C (OR: 1.9, 95% CI: 1.1-3.5, p < .05), and folic acid intake (OR: 4.8, 95% CI: 2.8-8.1, p < .001). CONCLUSIONS Data from the present study may indicate that serum folic acid is low in a group of Turkish adolescent girls. These low values appear to be associated with low income, and low dietary intakes of folic acid and vitamin C.