Background: To assess vitamin D in rheumatoid arthritis and its correlation with disease activity. Material and methods: A prospective, comparative study with one hundred individuals, fifty RA patients and fifty healthy controls, all in the eighteen to seventy-five years of age range, was done. Serum Vitamin D levels had been assessed in patients as well as controls and compared. In order to determine whether there is a link between the two, vitamin D levels in RA patients were also measured at various phases of disease activity. Results: The mean serum calcium levels were 7.94 mg/dl in the RA group and 8.66 mg/dl in the control group. This difference was statistically significant. 36 patients (72%) belonging to the RA group had serum Vitamin D levels <30 ng/ml, that is, they were Vitamin D deficient, whereas only 14 participants (28%) belonging to the control group had Vitamin D deficiency. The mean serum Vitamin D levels were 24.12 ng/ml in patients of RA and 36.87 ng/ml in the control group. This difference was also statistically significant. Significant results were obtained while correlating vitamin D levels with disease activity. Conclusion: In individuals suffering from RA, vitamin D insufficiency is more prevalent and may contribute to the onset or progression of the illness.