A recent report [S. Deville and J. Chevalier, J. Am. Ceram. Soc., 86[12], 2225 (2003)] has shown the new possibilities offered by atomic force microscopy (AFM) to investigate martensitic transformation-induced relief in zirconia. In this paper, we studied quallitatively the surface relief resulting from martensitic tetragonal to monoctinic phase transformation in yttria and ceria-doped zirconia by AFM. AFM appears as a very powerful tool to investigate martensite relief with great precision. The phenomenological theory of martensitic crystallography could be successfully applied to explain all the observed features. The formation conditions of martensite are discussed, as welt as ways of accommodating locally the transformation strain, i.e., self-accommodating variant pairs and microcracking. Variant growth sequences are observed. These observations bring new insights and explanations on the transformation initiation and propagation sequences.