The polymer precursor method is very useful to prepare Nb5+-stabilized nanocrystalline powders of t-ZrO2. The precursor solution is composed of zirconium oxalate, niobium tartrate, and poly(vinyl alcohol), which help to form a network matrix to disperse the metal ions homogeneously. Nb5+ is an effective agent to stabilize t-ZrO2, and ease of formation of the tetragonal phase increases with increasing dopant concentration. Thermal stability of t-phase is found up to 1700degreesC having 15 mol% Nb5+, prepared at 600degreesC with particle sizes of 35 +/- 5 nm.