Objectives: To test Rheumatoid factor (RF) IgM autoantibody in Patients with Rheumatoid Arthritis by various methods like latex agglutination, Nephelometer and ELISA. Comparative analysis of the sensitivity and specificity of the tests performed. Materials and Methods: The study was conducted for a period of six months from June 2018 to November 2018 in a tertiary care hospital in Chennai. 90 patients attending Rheumatology OPD or admitted in the ward with the diagnosis of Rheumatoid arthritis, satisfying the inclusion and exclusion criteria were taken up for the study. Inclusion criteria: Clinically diagnosed Rheumatoid Arthritis patient as per revised ACR 1987 classification criteria. Duration of symptoms (1yr- early (RA) 1 Yr. (Established RA). Exclusion Criteria: Those with systemic connective tissue diseases like SLE, Scleroderma, MCTD, Sjogren syndrome, those with chronic liver diseases, tuberculosis, subacute Bacterial endocarditis, Pregnancy, Lympho reticular malignancies are excluded for the study. Those with onset 16 years of age are also excluded. Under aseptic precautions about 3ml of blood was collected from each Patient. Rheumatoid factor (RF) IgM was tested for each patient by all three methods Latex agglutination, Nephelometry and ELISA. Results: IgM rheumatoid factor (RF) was detected in the sera of 90 patients with Rheumatoid Arthritis. The percentage of positivity for Rheumatoid factor by Latex agglutination, ELISA and Nephelometry were 41,64&60 respectively. Sensitivity and Specificity of ELISA when compared to nephelometry were 63 & 33% followed by latex agglutination 41 &59%. Conclusion: Though nephelometry is considered as gold standard, in this study ELISA was highly sensitive more even than nephelometry in Rheumatoid factor detection followed by latex agglutination.