Aim: Our aim was to evaluate maternal vitamin D levels of pregnant women in the third trimester. Material and Method: 44 pregnant women in the third trimester, applying to Taksim Hospital Gynecology and Obstetrics Department, from 1st February to 30th April 2005, were included in this study. Serum 25(OH) vitamin D, calcium (Ca), phosphorus (P) and alkalene phosphatase (ALP) levels were measured by radioimmunoassay (RIA) and otomation system, respectively. Results: The mean age of pregnant women was 25.4±3.5 years. Serum Ca levels were 8.87±0.42 mg/dL, P levels 3.58±0.64 mg/dL, ALP levels 395±92 U/L and 25(OH) vitamin D levels were measured as 11.1±3.80 ng/mL. Depending on the reference level of the laboratory, 25(OH) vitamin D levels were found below 10 ng/mL which is the lower limit for winter, in 31 (%70.45) cases and 10 - 25 ng/mL in 13 cases (29.54%). Conclusions: Mothers who applied to our Gynecology and Obstetrics Department have a poor vitamin D status. This is a significant risk factor with regard to clinical and sub-clinical vitamin D deficiency in the early infancy period.