Polycrystalline zirconia (3Y-TZP grade) specimens unreinforced and reinforced with multiwalled carbon nanotubes (MWCNTs) or silicon carbide whiskers (SiCws) were processed by powder metallurgy and studied by mechanical spectroscopy. The high-temperature mechanical-loss spectrum of pure 3Y-TZP presents mainly an exponential background. Doping 3Y-TZP with nano-sized reinforcements such as MWCNT or SiCw results in a decrease in the high-temperature background with respect to pure zirconia. It has been shown that these spectrum modifications by doping are associated with a better resistance to creep. (C) 2009 Elsevier B.V. All rights reserved.