The electrode temperature rise during the starting of an arc discharge lamp has been measured using the temperature‐dependent reflection coefficient of He‐Ne laser light from metal surfaces. Lock‐in techniques permit temporal resolution of about 3 ms, which is adequate to resolve 60‐Hz phenomena such as electrode heating during the ac cycle. Calibration curves obtained by pyrometric measurements of constant‐current tungsten ribbon lamps were used to relate the observed signal during electrode heating to its temperature. The technique described affords a nonintrusive method for measuring transient electrode temperature in an optically clustered environment with an accuracy of about 20%.