Background : To examine the potential association of vitamin D levels in development of RA and its severity, a study is being conducted to find out vitamin D levels in patients of RA in comparison to healthy controls and to find out correlation between rheumatoid arthritis and serum vitamin D level. Material and Methods : This cross sectional study was conducted at Narayan Medical College, Jamuhar, Sasaram. Bihar to find out the prevalence of vitamin D deficiency in Rheumatoid arthritis patients by analysis of serum vitamin D levels. Results : This study was a cross sectional study, conducted at a tertiary care hospital. Fifty patients of rheumatoid arthritis diagnosed according to the 1987 revised criteria of rheumatology were included in this study. Patients diagnosed with RA for more than a year, those having chronic renal failure, systemic lupus erythematosus, diabetes , any systemic illness and patients on enzyme inducer drugs or on calcium and vitamin D supplements were excluded from this study. Fifty healthy control subjects were selected from general population who were age and sex matched and were free from any systemic illness. We have compared the serum vitamin 25 hydroxy vitamin D3 levels among rheumatoid arthritis patients and healthy controls. Conclusion : Patients of RA, are at higher risk of falls and fractures by virtue of age and gender. The patient group who may benefit most from correction of vitamin D deficiency are older, post–menopausal and those with little or no sunlight exposure, non–white skin, individuals with malabsorption.