X-ray examination of nearly 300 panels of untreated and preservative-treated wood, exposed in an above-ground decay test, was chosen as a feasible means of obtaining a permanent record of the condition of the panels at the time of inspection, as an alternative to, and a possible confirmation of, other nondestructive methods of assessment and, finally, to explore the possibility of using x-rays as a quantitative measure of the severity of decay. Where decay was present, x-rays proved more accurate than visual assessment in defining its extent, but in undecayed wood, x-rays could produce shadows that could be misinterpreted as decay. -- AATA