Synopsis A new test of fire damage in concrete is proposed based on the technique of thermoluminescence. The thermoluminescence signal remaining in samples of sand extracted from concrete structures is shown to be an indicator of probable fire damage in concrete exposed to temperatures in the range of300°–500°C. The thermoluminescence test is shown to be easy to apply, to require only small samples and to be a more objective test than those in current use where reinstatement is being considered. An important feature of the proposed test is that it is sensitive to the thermal exposure experienced by the concrete rather than just the maximum temperature reached.