In this study, experiments were conducted to investigate the effect of hot isostatic pressing (HIP) on superplastic ductility of ZrO2/Al2O3 composite containing 40 wt.% Al2O3 at a constant strain rate of 1 X 10(-4) s(-1) and 1723 K. The results show that superplastic ductility obtained from HIPed specimen is higher than that of sintered one. The reason for this ductility enhancement is explained in terms of elimination of agglomerates in the sintered specimen. Also the effect of hot isostatic pressing on cavitation behaviour is quantitatively examined. It is shown that extensive internal cavities form during superplastic flow in sintered and HIPed specimens. The amount and size of cavities decrease with hot isostatic pressing stress. (C) 2002 Elsevier Science Ltd and Techna S.r.l. All rights reserved.