Objective. To determine the clinical usefulness of color duplex sonography in the diagnosis of giant cell arteritis as an alternative to temporal artery biopsy. Methods. From May 1998 to November 2002, 68 consecutive patients seen in our hospital with a clinical suggestion of active temporal arteritis were included. Forty‐eight patients were female and 20 were male, with a mean age of 77 years. Color duplex sonography with a linear array transducer (5–10 MHz) was used to assess temporal artery morphologic characteristics before a biopsy was performed. The main sonographic criterion for a positive diagnosis was visualization of a hypoechoic halo around the temporal artery. These data were compared with pathologic findings. The κ statistic was used to determine the level of agreement. Sensitivity, specificity, positive and negative predictive values, and accuracy of duplex sonography as a diagnostic test were assessed. Results. The color duplex sonographic findings were positive in 25 of 68 patients with a clinical suggestion of giant cell arteritis. The diagnosis was confirmed by biopsy in 22 patients; there were 4 false‐positive results and 1 false‐negative result by duplex sonography. The κ value was 0.84. Sensitivity, specificity, positive and negative predictive values, and accuracy for duplex sonography were 95.4%, 91.3%, 84%, 97.6%, and 92.6%, respectively. Conclusions. The use of high‐resolution color duplex sonography may replace biopsy in the diagnosis of giant cell arteritis.