Following media concern regarding the performance of hollow core concrete slabs in fires, full-scale tests of two slabs were conducted, with The European Commission on Prefabrication recommendations to prevent anchorage failure being incorporated into the construction. Previous failures had been attributed to incomplete drying prior to testing. One slab had all the joints filled and a structural topping of concrete to a minimum depth of 50 mm and with mesh reinforcement. The second had all the joints filled and hooked reinforcing bars placed in the joints over the supports. The fire loads consisted of 30 kg of wood/m2, with a calorific value of 19 MJ/kg. Very rapid heating rates were observed, with maximum temperatures above 1200 C. No significant spalling occurred, and it is proposed that previous problems were associated with inadequate curing prior to testing. Premature shear failure was not observed. 4 refs.