Background: Rheumatoid arthritis (RA) is an inflammatory disease. Predictors of disease activity include presence of joint inflammation, blood investigations such as erythrocyte sedimentation rate (ESR) and c-reactive protein (CRP). ESR is said to be imprecise as it is affected by aging, female sex, obesity, pregnancy, anaemia and polycythaemia. But it is inexpensive and easy to perform. CRP is produced as an acute phase reactant by the liver in response to interleukin 6 and other cytokines. CRP is more specific but costs more than ESR. Both tests are done in the rheumatology clinic of Hospital Seremban. Objective: To compare the usefulness of ESR and CRP as a predictor of disease activity in rheumatoid arthritis (RA) patients. Method: This was a retrospective study. The medical records of 248 RA patients who attended the rheumatology clinic, Hospital Seremban between 1 January 2004 and 31 Dec 2004 were reviewed. The following data were obtained: joint swelling and tenderness, other clinical features which indicate inflammation secondary to infection or trauma and inflammation of soft tissue, ESR, CRP, FBC and UFEME. Results: Data was analysed and the results showed that a total number of 248 patients were seen. There were 13 defaulters. Of the 248 patients there were 929 patients' visits. Of the total number of patients' visits where patients clinically had active disease, 80.2% had raised ESR while 88.8% had raised CRP. As for visits where patients had quiescent disease clinically, 57.3% had normal ESR and 36.5% had normal CRP. Conclusion: CRP is more sensitive but less specific than ESR. This suggests that we still should use both tests as they complement each other. ESR can serve as a countercheck for CRP and vice versa.