Objective: To establish the frequency of thyroid disorders among Rheumatoid Arthritis patients and its association with disease severity measured by DAS28-ESR.
 Study Design: Prospective longitudinal study.
 Place and Duration of Study: Department of Rheumatology, Federal Government Policlinic Hospital, Islamabad Pakistan, from Jan to Jun 2021.
 Methodology: The study included 87 consecutive patients either gender with Rheumatoid Arthritis visiting Rheumatology OPD. Thyroid profile and DAS28-ESR were performed in all the patients.
 Results: Out of 87 patients, 73(83.9%) were females, and 14(16.1%) were males. The mean age was 45.54±13.50 years. The mean DAS28-ESR was 4.45±0.68, with a minimum DAS28-ESR of 1.25 and a maximum of 8.40. The Disease severity calculated by DAS28-ESR was mild in 19(21.8%), moderate in 44(50.6%) and severe in 24(27.6 %) patients. The thyroid gland was abnormal in 23(26.1%) patients. 18(78.2%) of 23 patients with thyroid disorders belonged to the moderate to severe Rheumatoid arthritis disease activity group.
 Conclusion: Thyroid disorders are very common in Rheumatoid Arthritis patients. Thyroid workup should be part of investigations of Rheumatoid Arthritis for early detection of thyroid disorder and better disease control.