Microstructure of plasma-sprayed yttria-stabilized zirconia coatings (8YZ) was characterized by the measurement of surface roughness, hardness, and pore size distribution and was correlated with thermal fatigue life. It was confirmed that the coatings which had greater roughness tended to show both lower hardness and higher porosity. Furthermore, such coatings were found to have a longer thermal fatigue life. We propose that measurement of the roughness of 8YZ coatings is useful as a non-destructive evaluation method for predicting thermal fatigue life.