The objective of this present study was to determine serum 25-hydroxyvitamin D (25(OH)D) concentrations in patients with RA and to establish its correlation with disease activity. This study was performed on fifty-five consecutive patients RA fulfilling the American Collage of Rheumatology (ACR) criteria for the classification of RA and forty-five healthy subjects. Serum 25(OH)D levels were measured using Elecsys 25(OH)D reactive kit