Stabilized ZrO2 membranes (e.g. 8YSZ) have great potential due to their excellent thermal stability. In this paper, we present a new synthetic methodology to produce 8YSZ membranes on commercial macroporous alpha-Al2O3 supports. The resulting membranes have an average pore size of similar to 5 nm and similar to 3 nm, respectively, and a thickness approaching 2 mu m. In various harsh stability tests, these membranes were tolerant to hydrothermal conditions (300 degrees C, 15 bar), high temperature (700 degrees C), and a high pH (NaOH, pH 14, 80 degrees C). They also demonstrated a suitable MWCO (15000 Da PEG; < 3000 Da PEG) and permeance (145 kg h(-1) m(-2) bar(-1); 40-50 kg h(-1) m(-2) bar(-1)) for commercial ultrafiltration processes. Importantly, they can also be considered for the production of novel graded macro-/meso-/microporous membrane systems, replacing the widely used but unstable mesoporous gamma-Al2O3 membranes. At the end of this paper, we demonstrate that the synthetic methodology presented is also useful for producing membranes of other promising materials, including stabilized CeO2.