The purpose of this study was to evaluate the use of spectral Doppler in the assessment of patients with rheumatoid arthritis (RA). The study group consisted of 32 patients with RA followed up clinically and by ultrasound using the resistive index (RI) measurements in the patients' wrists as indicator of inflammation. Lower RI values were recorded at baseline compared with data derived at 1-y follow-up examination from patients in remission and normal controls (p < 0.001). Discrimination by spectral Doppler between patients in remission and those who had a relapse within six months after the examination was possible with an accuracy of 95.6%. Patients in remission who had a flare-up within six months after the examination had significantly lower (p < 0.01) RI values vs. patients who remained in stable remission. In conclusion, RI measurements may serve as an objective marker of disease activity and potentially as a predictor of the disease course in RA.