This chapter describes the vitamin plasma concentration data collection, preliminary analysis and results of the Euronut SENECA study. Blood plasma was collected from approximately 2500 elderly subjects born in 1913-1918 living in 17 small towns in 11 European countries, and the plasma levels of carotene, retinol, alpha-tocopherol, vitamin B12, folic acid and pyridoxal 5'-phosphate were determined. There were very large within- and between-centre differences in vitamin levels with no definite geographical pattern emerging. The vitamin status for retinol and folic acid was adequate in all centres. The prevalence of biochemical vitamin B6 deficiency was widespread and reached over 50% in some centres. Vitamin B12 biochemical deficiency was limited to ten centres and its prevalence was 1.6%-10%. Vitamin E biochemical deficiency was found in seven centres and varied from 0.5% to 25%.