Well-aligned, densely distributed ZrO2 nanorod arrays were fabricated using a non-catalytic, template-free metal-organic chemical vapour deposition process at a reaction temperature of 1000 °C. The reaction temperature was found to play a key role in product morphology, with particle thin films obtained at 550 °C and nanorod arrays produced at 1000 °C. Increasing the reaction temperature led to the emergence of the medium-temperature tetragonal phase from the dominant low-temperature monoclinic phase, which is advantageous for anisotropic growth necessary for the nanorod formation. With the same deposition process, yttria-stabilized zirconia nanorod arrays of polycrystalline cubic phase were fabricated by co-feeding the dopant precursor, YCl3, with the zirconia precursor, Zr(C5H 7O2)4. The present work demonstrated the first example of monoclinic to tetragonal phase-transition assisted one-dimensional (1D) growth, and the concept can be extended to the formation of 1D nanostructures of materials possessing the monoclinic-tetragonal polymorphism.