Abstract Background/ Aim: Vitamin D deficiency is highly prevalent condition. The aim of the present study was to assess vitamin D status in people living in Turkey. Methods: This was a single center, retrospective study on subjects who attended to Acibadem Hospitals and outpatient clinics for the measurement of 25(OH)D. Data on 25(OH)D was available for 179464 subjects. Results: Mean 25(OH)D was 19, 56 ±0,04 ng/mL and mean age of the subjects was 39, 28 ± 0, 05 years. Mean 25(OH)D of women were lower than men; (18, 79 ± 0, 05 vs 22, 07 ± 0, 09 ng/mL; p<0.001). 25(OH)D of 111510 subjects (62, 1%) was <20 ng/mL. 42592 (23, 7%) were between 20-32 ng/mL. 24276 (13, 5%) of the subjects demonstrated normal 25(OH)D levels. 25(OH)D level was excess in 776 (0, 4%) of the subjects. Three hundred and ten (0, 2%) had toxic 25(OH)D levels. Totally 85, 9% of the subjects had low 25(OH)D levels. Adolescents, adults and elderly had lower 25(OH)D levels than newborns and children (p<0.001). Vitamin D deficiency and insufficiency were more common in adolescents, adults and elderly than in new born and children (p<0.001). Conclusıons: A considerable number of subjects in our study had 25(OH)D below the normal ranges for all age groups except neonates, demonstrating that vitamin D deficiency and insufficiency in western part of the country is a major healthcare concern in Turkey.